Welcome! Ultralight backpacking is my passion, and keeping up on new technologies, gear, and techniques relevant to UL backpacking is what floats my boat. I'm always looking for the lightest, most functional gear to improve a lightweight or ultralight backpacking kit, and report my impressions and field testing results here. For hikers wanting to keep up on the latest and greatest ultralight backpacking gear, this is a good place to hang out. Also, there is a lot of information here (and on our informational website Southwest Ultralight Backpacking) on useful techniques and backcountry etiquette -- food for thought for hikers wanting to lighten their load and their impacts.

My goal for Ultralight Insights is to understand, test, and report on new technologies and gear of interest to lightweight and ultralight backpackers. It's a passion after all, so we just plain enjoy talking about it. I hope readers will add their own wisdom and comments, respond to my questions, ask their own questions, and correct me if I get something wrong. Happy hiking! Will

Sunday, February 18, 2018

GEAR REVIEW: Patagonia Nano-Air Light Hybrid Jacket

By Will Rietveld

I reviewed the Patagonia Nano-Air Jacket a year ago and found the jacket’s active exertion comfort range occurs at temperatures lower than I normally encounter. In other words, it is more insulation than I need in my location for high exertion activities. Granted, it is a very attractive, and warm, jacket for less active endeavors.

Still wanting to test the concept of “breathable insulation”, I opted to next test Patagonia’s Nano-Air Light Hybrid Jacket, which is a lighter weight version of the Jacket.

Here’s the stats: the Nano-Air Jacket has 60 ounces/square yard polyester insulation, while the Nano-Air Light Hybrid Jacket has 40 ounces/square yard insulation, one-third less.  The fabrics in the two jackets are very similar.

The whole idea behind these jackets is to provide extended range comfort and avoid overheating during aerobic outdoor cool weather activities. So, how does the lighter weight Nano-Air Light Hybrid Jacket perform in active exertion conditions?

Specifications and Features

Patagonia (www.patagonia.com)
Nano-Air Light Hybrid Jacket
Outer shell is 1.3 oz/sq yd nylon ripstop, lining is 2 oz/sq yd nylon plain weave, both with stretch and DWR
Frontside fabric: 40 CFM, backside fabric 130 CFM
40 oz/sq yd Full-Range polyester
Size men’s Large tested: measured weight 10.85 oz; mfr specification 10.1 oz for size Medium
Full-height front zipper, slim fit, stretch fabric, wind-resistant frontside fabric, breathable backside fabric, 2 zippered handwarmer pockets, elastic hem and cuffs, thumbloops


The Patagonia Nano-Air Light Hybrid Jacket is designed to be a high performance garment. Patagonia’s synthetic Full-Range polyester insulation is analogous to Polartec Alpha, which is a “breathable insulation” meant to keep you comfortable during aerobic activities in cool temperatures, and provide an extended comfort range.

The frontside of the jacket is insulated and has a tighter weave shell fabric to provide some wind resistance (40 CFM); the backside of the garment is uninsulated and has a knitted weave to provide greater breathability (130 CFM). Both the shell and lining have a DWR finish, which I previously tested to be very effective.

Close up of the insulated frontside and knitted backside.

Field Testing and Performance

I tested the jacket on 20 outings consisting of day hiking, snowshoeing, cross-country skiing, backcountry skiing, and backpacking. Testing was mostly done in cool temperatures ranging from 15 to 40F.

Fit – Excellent, as I have found with all Patagonia garments. The garment’s body is extra long to cover the butt, and the sleeves are longer too. Its slim cut makes it fit closer to my body, so it’s not bulky, and layers well.

Features – The hand pockets are nice and roomy, and zip for security. I like the stand-up collar to provide some sun protection for my neck. The thumb loops are handy to donn the jacket over a baselayer or other garment.

Wind-Resistance – The tighter front fabric provides needed wind resistance so a cold wind does not readily penetrate.

Breathability – The frontside fabric does allow for some air exchange; it’s basically a trade-off between wind resistance and insulation. The backside fabric is much more breathable, but it is often mostly covered by a day pack or backpack. Breathability is maximized in activities like running, bicycling, and cross-country skiing where one does not normally carry a pack.

Performance – The graph below tells a lot about the jackets performance while speed hiking an undulating trail, carrying a daypack, in temperatures ranging from 25 to 30 F and calm air. The test was done before sunrise to avoid sun warming. I recorded the temperature and relative humidity inside the jacket with a Kestrel 4000, located at mid-chest, at 10 second intervals.

Test data for Patagonia Nano-Air Hybrid Jacket

Note that the jacket’s insulation maintained a fairly constant internal temperature in the 65 to 70 F range, which is good. However, humidity steadily built up inside the jacket as I hiked, and flattened out at about 65%. That indicates that the jacket’s fabric breathability was not enough to exhaust the moisture, allowing it to build up.

In terms of perceived comfort, it took about 45 minutes for the humidity inside the jacket to build up to the point where the jacket felt somewhat steamy inside and time to open the front zipper to increase ventilation.

But that is only part of the comfort story, because the test was done without any influence from the sun. I live in the Southwest US, where we get a lot of sun, and the sun is warm even in the winter. Thus the radiant heat from the sun has a big influence in jacket comfort, even in cold air. There were many occasions when I simply had to take the jacket off because it was too warm, when the air temperature was in the 30s and 40s F.

Issues – I found that the jacket’s fabric gets dirty fairly easily, as evidenced by the ring around the neck (from sunscreen) in the photo. And the photo was taken after laundering the garment. Also the jacket incurred some abrasion damage from a skiing fall, so it requires careful use.


Although the Nano-Air Light Hybrid Jacket was often too warm for me in the sunny Southwest, I found its sweet spot is cool, overcast, and breezy conditions, which is what the jacket is designed for. When I had those conditions, the jacket performed well for maintaining comfort over an extended range. In locations where it is overcast or breezy much of the time, or the sun is low, this jacket is capable of providing comfort over an extended range of conditions, as claimed.

The more consistent conditions are – namely overcast, cool, and breezy – the better this jacket will perform. Then all is good. The problem I found is variability; when the sun comes out or the wind stops, I get too hot. Opening the front zipper regulates comfort to some extent, but eventually it is not enough. The Nano-Air definitely provides some extended comfort, but the end result is usually the same – the jacket has to come off. 

Bottom line, it’s a very attractive, great fitting, hi-tech jacket that helps to provide extended comfort in cool, overcast, breezy conditions, but in my situation those conditions don’t exist for very long. If you exercise where those conditions are more typical, then this jacket is for you. However, don’t expect a silver bullet, the breathability part is subtle.

GEAR REVIEW: Crescent Moon Eva All-Foam Snowshoes

By Will Rietveld

This is a new snowshoe with no metal in it; it’s made of EVA foam, the same stuff used for cushioning in the midsole of athletic footwear. It’s received numerous awards for innovation, which is well deserved. It’s fairly light weight at 3.5 pounds per pair, which is true compared to many conventional snowshoes that weigh over 4 pounds per pair.

The new Crescent Moon Eva All-Foam Snowshoe is made of dual-density EVA foam; there is no metal in them. The bottomside has a tread molded in that makes a track in the snow like a snow tire. A hard plastic plate with spikes in inlaid into the bottom of the shoe for climbing traction.

And they certainly attract attention, as was the case when I tested the Eva All-Foam Snowshoes with experienced snowshoeing friends. They all asked how well they perform – traction on uphills, downhills and sidehills – and how do they feel without a binding hinge. That’s what I wanted to know too, which was my reason for testing this unusual snowshoe.

First a little background: I have been testing snowshoes for 14 years, and have published numerous reviews and articles on snowshoes in Backpacking Light Magazine during my 10 year tenure there. I snowshoe with a bunch of hardcore seniors who love to make their own trail through rough, steep, and very scenic terrain. So we know snowshoes, and that’s why my companions were so inquisitive.

So, how did these Eva All-Foam Snowshoes perform in different types of terrain and snow conditons? Read on.

Specifications and Features

Crescent Moon (www.crescentmoonsnowshoes.com)
Eva All-Foam Snowshoe
EVA foam and hardened plastic.
Embedded adjustable hypalon over the foot and heel straps with hook and loop closure
8 in x 24 in
Measured weight 3.5 pounds, mfr specification 3.5 pounds


The topside of the snowshoe is a softer EVA with the binding embedded. The bottomside is a molded harder EVA with a traction tread molded in plus an inlaid hard plastic plate with sharp spikes.

These snowshoes are definitely a new concept; some details: 

  • They are made of dual density molded EVA foam that is flexible.
  • The upper layer of the foam (white) is softer and has the binding anchored into it, so it’s not removable or replaceable.
  • The bottom layer of EVA is harder and has a traction tread molded into it, like a snow tire.
  • A hard plastic traction panel sporting 10 clusters of three-pronged spikes is inlaid beneath the binding, which serves the function of crampons in a traditional snowshoe.
  • The snowshoe does not have a binding hinge; instead it has lots of rocker (curvature) and flexibility to facilitate walking.
  • Since there is no binding hinge, the tail of the snowshoe does not drop when you lift your foot; rather the snowshoe stays flatly attached to the bottom of your boot.
  • The foam construction makes the snowshoes somewhat lightweight at 3.5 pounds, but they are not as light as they look, and certainly not the lightest ones to be found.
The simple binding is made of Hypalon rubber. Two adjustable top straps and one heel strap fit boots from a women's 7 to a men's 14. The underheel strap at the back is my gaiter strap.

There is no doubt that these snowshoes are unconventional, but how do they compare to conventional snowshoes? And are they any better?

Testing and Performance

I obtained a pair of the snowshoes for a few weeks to test them out, and had the opportunity to try them out in shallower snow, wet snow, and deep snow.

My first impression, in shallow (12 inches deep) and wet snow, is they feel the same as conventional snowshoes, which is remarkable since I was expecting some sort of adjustment to them. They walked, climbed, descended, tracked, and gripped as well as conventional snowshoes. They broke trail just fine. I did not have any icing up problems when I went from wet (open sun) snow to cold (shade) snow.  The peripheral lugs in the bottom tread gave the snowshoes good lateral stability. I had a hard time finding any fault with them.

Then I tested them on deeper softer snow (30 to 36 inches deep), and discovered their limitations. When following a few snowshoers who created an 8 to 10 inch trench, I sank in much deeper – these snowshoes lack adequate flotation for softer snow. Exacerbating that problem, the flat attachment of the snowshoes makes then act like scoops – snow  piles up on top of the snowshoes, which I have to lift when I pull them up out of the holes. They are laborious to use in soft snow, and forget about breaking trail with them in deeper soft snow.

I noticed after using the snowshoes on three all-day hikes (there were used some before I got them)  that the hard plastic spikes on the bottom are already rounded off, making one wonder about the longevity of these snowshoes. There is no noticeable wear in the molded EVA tread. Note: I did not walk on rock or pavement with the snowshoes, although I did walk on hard ice and hit an occasional rock buried in the snow.


I found from my testing that the Crescent Moon Eva All-Foam Snowshoes are best described as an entry level or beginner snowshoe best suited for packed trails. If you are making your own trail with a group of people, you want to be near the end of the line.

In soft deeper snow, because of their teardrop shape, they lack the flotation of other snowshoes the same length. Added to that, their flat position loads them with snow, making them laborious to lift. Overall, they are very unsuitable for breaking trail, or following a few others on a newly broken trail.

The hard plastic spikes on the bottom allow these snowshoes to climb quite well in firm snow, and I did not find the lack of a pivot point to be a limitation. When I am steeply climbing I concentrate my weight on the toe crampons of conventional snowshoes, but I found the spikes on the foam snowshoes seemed to function as well. However, the spikes are getting rounded off after only a few trips with normal wear and tear, which makes me wonder what the longevity of these snowshoes will be. Conventional snowshoes, with metal crampons, will last a long time.

Version 2 of the Eva All-Foam Snowshoe is coming in fall 2018 (right). It will add aluminum crampons to make them climb better, with no weight gain. Also note that the molded tread is revised too. Looks like they won't be all-foam anymore. The aluminum crampons should help with both traction and longevity. The current version is shown in the left photo.

The Eva Foam snowshoes cost less than most conventional snowshoes, and weigh a bit less, but I believe the old adage applies “you get what you pay for”. For example, the MSR Lightning Trail snowshoe in a 25-inch length weighs 3 pounds 6 ounces (2 ounces less), has a metal frame and crampons, provides serious traction in all directions, and costs $220 ($60 more). That’s where I would put my money, but I'm more of a hardcore snowshoer.

It's important to evaluate these snowshoes for what they are -- less expensive snowshoes for beginner and intermittent snowshoers who mainly travel on packed snow. They are simpler to put on and use, with no learning curve; simply walk on them. And for that niche they are a good choice. They are unique, simple and easy to use, function very well, and attract a lot of attention.

Tuesday, January 30, 2018

Highlights from the Outdoor Retailer Winter Market 2018: Interesting and Useful New Gear for Lightweight Backcountry Travel

By Will Rietveld and Janet Reichl

As you probably know by now, Outdoor Retailer has moved to Denver Colorado and this is the first show at the new location. Also the winter OR show has been combined with SIA, which is the snowsports industry trade show, a complementary combination.

We cover the show to find gear of interest for lightweight backcountry travel: backpacking, canoeing, kayaking, biking, skiing, snowshoeing, and mountaineering. Most of the gear we find at OR is in the lightweight category, although we find some ultralight items as well. For gearheads, its just fun to keep up with new gear and technologies that lighten our load and improve our enjoyment of the backcountry.

Lifestraw Flex Water Filtration System. We reported on this last summer but the product was more of a prototype then. The 0.65 liter flask is made of TPU and has a fairly large opening for the filter unit to screw in. Weight is 3.05 ounces for the flask and filter; cost is $35, and it’s available in spring 2018.

Kahtoola Instagaiters. This new line of lightweight gaiters will come out in January 2019. Four styles are: Low (1.7-2 oz, $39), Mid (2.3-2.6 oz, $49), Navigaiter (tall, 6-7 oz, $75), and Levagaiter (tall, 4.4-5 oz, $85). Each has a zipper that angles to the side (water-resistant on the tall gaiters)  and a durable TPU underfoot strap, which is replaceable. The Levagaiter (left one in the right photo) is made of Gore-Tex fabric, making it a very lightweight breathable gaiter. The Navigater has a Gore-Tex fabric upper and durable ballistic nylon lower, so it weighs a bit more. The tall gaiters (in black only) will be available from REI in July 2018.

Tinkle Belle. We have seen various devices for women to pee in the woods, and perhaps this is the best one yet. Its claims to fame are a better fit to the female anatomy, and it moves urine farther away from the body. To use it, you only have to unzip your pants, not take them down, or push your swimsuit aside. Available now at www.thetinkerbelle.com for $25. A case is included and it weighs 1.75 ounces.
Outdoor Element Firebiner. This one ounce gadget is a multitool on a carabiner. It’s a carabiner, screwdriver, cord cutter, and fire starter (see right photo for complete list). MSRP is $15 and its available now.
Maxsun Canister Stove. How about a 0.95 ounce canister stove? This one coming from Maxsun, a South Korea company, is super light and compact. They are looking for a US distributor and they say it will be available in three months. Stay tuned.
Aketta Cricket Protein Products. Keep saying “it’s all in my mind”. We covered chocolate products with cricket protein before, and to be truthful, we couldn’t taste the cricket part. That’s true of Aketta’s granola ($6 for a 5-ounce package), but they also sell pure dried flavored crickets (inset, $4 for a 1-ounce package), which is a little harder to get past the gums. We tried them and found them crunchy and flavorful. They also have pure cricket protein powder ($15 for 4 ounces) which can be added to smoothies and other concoctions. Available now.
Ostrim Meat Sticks with Ostrich. The exhibitor, who formerly raised ostriches in Texas, claims that ostrich is the leanest red meat with high protein. They now buy the meat on the open market, and claim to be the largest ostrich meat buyer in the US. Their “meat sticks with ostrich” are beef + ostrich. They also have elk and turkey meat sticks without ostrich. Cost for a 1.5 ounce stick containing 14 grams of protein is $2. Available now.
Aftershokx Bone Conduction Headphone. We tried their lightest model, the Trekzair weighing 1.05 ounces/pair, and were impressed with their clarity and volume. They use Bluetooth to pick up music and talk on the phone. MSRP is $179, but they can be found for $149; available now.

Yukon Charlie Elite Snowshoes. The new Elite is their top of the line and is available in three lengths: 21 inches ($199, 3.89 pounds/pair), 25 inches ($199, 4.2 pounds/pair), and 30 inches ($199, 4.8 pounds/pair). They are reasonably lightweight for an aluminum frame snowshoe. The bottomside of the frame is serrated, and there are toe and heel crampons, as well as a heel lifter. Their Northwave Spin binding compresses the boot from the side, not the top, which is more comfortable. There is a pullcord to release the binding. Available around September-October 2018.

Crescent Moon All Foam Snowshoes. These came out in fall 2017 and are a new concept in snowshoes. They are made of different densities of EVA foam (like the midsole in a running shoe or boot), have a hard TPU plastic tread on the bottom, and have a lot of rocker (curvature). They work like a snow tire on snow. Version 2 coming in fall 2018 will add aluminum crampons (right photo) to make them climb better, with no weight gain. The current ones come in only one size (about 25 inches), weigh 3.5 pounds/pair, and sell for $159; available now. 

Big Agnes Tiger Wall UL Tent. Tents keep getting lighter. The Tiger Wall is a two-person, double-wall tent with two doors and two vestibules that weights just 2 pounds 3 ounces and costs $400. A three-person version will weigh 2 pounds 11 ounces and cost $450. Note the floor is wide enough for two standard air mattresses side by side, and headroom is very good in both height and width. The interior is ultralight mesh, with three storage pockets. The floor and fly are 15 denier nylon with a silicone coating on the outside and polyurethane on the inside. This one looks to be a winner; available fall 2018.

Big Agnes AXL Sleeping Pad. We covered this last summer, but the details were not complete then, and it also bears repeating. This is a full size, 3-inch thick air mattress weighing as little as 9.6 ounces. It will be available in two sizes: 20x72x3 uninsulated (9.6 ounces, $140) or insulated (10.6 ounces, $180), and 25x72x3 (13 ounces). They have a wide-opening valve that is compatible with an available inflation bag for fast inflation. Available spring 2018.

Soto Amicus Canister Stove. This new model is not regulated, weighs 2.55 ounces, and costs $40 without an igniter or $45 with an igniter. A regulated version, the Windmaster, weighs 3.15 ounces and costs $75. Both have a convex burner head to resist the effects of wind. They come with two different detachable pot supports. Available now. I am very partial to Soto stoves, and would be willing to carry a little extra weight to have their performance and reliability.

Leatherman Multi-Tool at 35 Years. We were privileged to attend a breakfast to hear the remarkable story of Tim Leatherman and the development of his multi-tool. Tim is a modest and articulate mechanical engineer who recognized the need for a multi-tool while fixing a Fiat in Europe, then spent 8 years developing the tool and struggling to find a market for it. That finally happened in 1983 and the rest is history; the company now has 400 employees and makes 35 models sold around the world. Very inspiring.

Altra Lone Peak 4.0. It wasn’t long ago that we reported on the Lone Peak 3.5 and tested it. The 3.5 was more of an upgrade but the 4.0 will be more of a makeover, in a good way. As before, it will be available in Low and Mid styles, mesh upper or waterproof-breathable upper. The latter will be eVent in the new version, rather than NeoShell. Other major changes are a newly designed TrailClaw tread with new rubber and grip pattern, a new rock plate shaped like a foot with long toes to provide more lateral stability, and a five-layer outsole. The mesh version is dialed in to make it just right for breathability and durability. I was so excited I forgot to get weights and MSRPs, but they should be similar to the current version.

Patagonia Capeline Air Baselayers. Their popular Capeline baselayers will now be available in four versions: Air, Thermal, Midweight, and Lightweight. The new Air version is knitted as one piece, meaning no seams, akin to printing it on a 3-D printer. The women’s version (right) has a bit more texture for more warmth. The yarn is 40% recycled polyethylene and 51% merino wool. We were unable to get the garment weights, but they appear to be very lightweight. A hoody version is $149 and a crew is $129; available now at www.patagonia.com and a little later in retail stores.

Patagonia Micropuff Jackets and Vests. The newest version of the popular Micropuff Jacket will feature Plumafill insulation, which is made from recycled polyethylene bottles. The insulation is in sheet form and the garment is sewn with minimal seams. Versions will be men’s and women’s jackets with or without a hood, and men’s and women’s vests. The hoodie is $299, jacket is $249, and vest is $199; available September 2018.

Western Mountaineering Quilts. Yep, quilts coming from WM. They will feature 7d fabric with an acrylic “kiss coating”, 850+ fill-power down, easy to use cord pad attachment, a wrap-around closure system, and an innovative collar design to seal in heat. The Nanolite has a 38F rating, weighs 11 ounces (12.5 ounces in size Long), and costs $330 ($345 for Long). The Astralite has a 26F rating, weighs 16 ounces (17.5 ounces for size Long), and costs $400 ($415 for Long). They will be available in spring 2018. As you can see, I tried one out and found the 6-foot Regular length a little short for my 6’ height, so I would need the Long. I was impressed with the loft of these bags, so they should be true to their temperature ratings.

Mountain Hardwear Ghost Whisperer Down Pants. A new addition to the Ghost Whisperer line is an ultralight down pant, which will be arriving in fall 2018. They are insulated with 800 fill-power Nikwax hydrophobic down. Weight is 7.8 ounces and MSRP will be $250. The beauty of down pants is they weigh about the same as a baselayer bottom, but provide a lot more insulation.

Monday, January 29, 2018

Highlights from the Outdoor Retailer Winter Market 2018: Introduction + New Technologies and Trends

By Will Rietveld and Janet Reichl

OR Moves to Denver

Following through on its ultimatum to leave Utah if Utah politicians persist with their push to privatize public lands, the Outdoor Retailer Trade Show has moved to Denver Colorado, in a state that strongly values its public lands and their connection to people and business. This was the first show at their new home at the Colorado Convention Center in downtown Denver. As you can see from the photo, the Colorado Convention Center is a beautiful facility, with enough room (barely) to contain the entire trade show under one roof, and provide easy access to hotels and restaurants.

The Colorado Convention Center in downtown Denver has 2.2 million square feet of exhibit space, meeting rooms, ballrooms, and a theatre. (Photo by US Green Building Council)

We couldn’t help but compare the facility to the Salt Palace in Salt Lake City. Navigation was easier in the Salt Palace because we had some landmarks to go by, but on the enormous rectangular conference center floor at the Colorado Convention Center it was very challenging to navigate. More signage is definitely needed for the next shows in July and August. We also missed the good people in Salt Lake City who (contrary to Utah politicians) worked hard to accommodate the many needs of the trade show and its attendees.


The outdoor industry is one of the most progressive in the world in terms of sustainable manufacturing and strongly supporting our public lands. Over the past few years manufacturers have made great strides to reduce environmental impacts from the manufacture of their products and increased use of recycled content. Congratulations and thank you!

The elimination of PFC-based DWRs is a case in point. The problem is the process contaminates a huge amount of water. The current substitutes have a serious downside; they don't last very long. However, a new chemistry developed by Green Theme International (http://www.greenthemeint.com/) called Aquavent is completely waterless and outperforms previous water-repellent finishes. They call it a HDF (High Definition Finish) rather than a DWR. Briefly, the chemical is cross-linked to the fibers through a heat and pressure process, which is amenable to adding dyes, antimicrobials, etc. at the same time. It becomes part of the fiber rather than a surface coating on fabric. The treated fiber is then woven into fabric. And fabric treated via the Aquavent process is softer and less slippery, and doesn’t need to be restored like a conventional DWR.

Marmot will be introducing Aquavent treated rainwear in their ECODry line of garments for spring 2018. The Phoenix Jacket (above, $175, 7 ounces) is the lightest one in the line. Pants are also available. (Marmot photo)

Gore-Tex Infinium

Gore made the biggest reveal since their original Gore-Tex fabric – they are moving beyond waterproof/breathable fabrics with the introduction of Gore-Tex Infinium technologies in fall 2018. Infinium technologies are comfort-tested performance constructions in four categories: soft-lined garments, insulated garments, stretch gloves, and footwear. These products move Gore beyond waterproof/breathable fabrics. Utilizing the Gore Biophysics Lab and Environmental Chamber in Maryland, Gore will develop constructions (combinations of fabric, membrane, insulation, linings, etc.) with optimized performance, which includes breathability, stretch, water-resistance, wind-resistance, warmth, moisture management, thermal management, form fit, and comfort. Those attributes will be optimized to the purpose of the garment. The majority of these constructions will be water-resistant, but not waterproof, and will be tagged with a white diamond logo. Current waterproof fabric constructions will continue to be tagged with the familiar Gore-Tex black diamond.

To be clear, Gore will work with garment brands to develop and test desired Infinium constructions, and the garments will be manufactured and sold by those other brands. This is the same model as the present Gore-Tex waterproof-breathable fabrics.  Gore Wear, their internal house brand, will also leverage some of these technologies.

Some examples of Gore Infinium:

Gore-Tex Infinium Soft-Line Garments will feature a thin Gore-Tex ePTFE membrane on the outside, which is nearly invisible on the left jacket, but makes the right one look much like a leather jacket. They are stitched-through so they are highly wind-resistant and breathable, but not waterproof.

Gore-Tex Infinium Insulated Garments can have a thin ePTFE membrane on the outside, over down or synthetic insulation, to provide breathability as well as wind and water resistance. For Fall 2018, Gore, working with strategic brand partners, will unveil Gore-Tex Infinium Thermium footwear in a line of women’s shoes built for everyday lifestyle use.

The existing Gore-Tex Windstopper technology, as in this wind and water-resistant softshell, will move into the Infinium category.

Synthetic Insulations Put the Heat on Down

At each succeeding OR we see more advances in synthetic insulation to make it more closely mimic down insulation and marketing to advance consumer acceptance. It’s working; a recent survey published in Outdoor Insight Magazine found that 37% of respondents prefer synthetic insulation, 28% prefer wool, and only 25% look for down. Puffy jackets are nice and warm, but consumers seem to prefer less bulky closer-fitting synthetic jackets that are also warm. Manufacturers like synthetic too, because insulation prices are not as volatile as down.

Polartec introduced their new Power Fill insulation for static warmth, which is 80% post-consumer recycled polyester content. Unlike Polartec Alpha insulation, which is breathable insulation intended for active comfort, Power Fill is intended to keep you warm when you are less active. It comes in sheets in six weights (60 grams to 120 grams), is quite durable, and does not require a carrier scrim to hold it in place.

Primaloft is introducing Thermoplume, which are clusters of polyester insulation (virgin, not recycled) which can be blown into the baffles of a jacket, creating a down-like feel and performance. This type of insulation is in the Primaloft Black category and is available now. The insulation value is roughly equivalent to 550 fill-power.

Tuesday, December 5, 2017

GEAR REVIEW: Big Agnes Flume UL 30 Sleeping Bag

The Big Agnes Flume UL 30 is a cutting edge ultralight down bag designed for warmth. Its pricing is similar to other bags in its class, but the design features and details are a level above.

By Will Rietveld

Because key sleeping bag specifications are often lacking, it’s “baffling” for a consumer to compare them and make an informed purchase decision. In this review I share some of my wisdom from testing numerous ultralight sleeping bags, and present my evaluation of the new Big Agnes Flume UL 30 mummy bag.

Introduced in spring 2017, the Flume UL 30 (and its sibling the Hitchens UL 20) is a truly ultralight down sleeping bag from Big Agnes. Prior to this, Big Agnes offered literally dozens of high quality, utilitarian sleeping bag models for most any outdoor activity, except ultralight backpacking.

A good ultralight mummy style sleeping bag has thin shell fabric, a minimal zipper, high loft down (850 fill-power or greater), a good fitting hood, and enough shoulder girth to enable wearing camp clothing inside the bag to extend its warmth. So, how does the Flume UL 30 perform in relation to these criteria?

The Big Agnes Flume UL 30 sleeping bag features 850+ fill-power water-resistant down, ultralight shell fabric and  Insotect Flow construction weighs 24.8 ounces in size Long, and costs $500.

Specifications and Features

Big Agnes (www.bigagnes.com)
Flume UL 30 (size Long tested)
Downtek water-resistant down, ultralight high-tenacity ripstop nylon outer shell (with DWR) and lining, 40 in YKK #5 zipper
Measured weight 24.8 oz; mfr specification 24 oz
850 fill-power Downtek water-resistant down, Insotect Flow™ construction, 3-D anti-snag draft tube, vertically structured side walls integrating contoured baffles, contoured hood baffles, oversized interior anti draft collar, ergonomic foot box, ultralight high tenacity shell fabric, low profile cordlock lets you un-cinch the hood with one hand, minimal 40” zipper, zipper garage, interior fabric loops for sleeping bag liners, exterior loops for hang drying or storage, mesh storage sack, nylon stuff sack
Size Regular $469.95; size Long $499.95


We are not a society of string beans; far from it. Yet numerous ultralight mummy bags are simply too slim (shoulder girth of 59 to 60 inches) for the average hiker. I’m 6 feet tall, 165 pounds, and normally wear a size Large shirt – which is fairly average – but I can hardly close the zipper on a bag with the above girth if I am wearing an ultralight down jacket. If you are smaller than me, then you should be okay with a trim bag. If you are my size or larger, read on.

Ultralight backpackers like to carry an ultralight down jacket to wear in camp for warmth, and then wear it inside their sleeping system to extend its warmth. That’s an important technique to save weight and increase efficiency. To do that, an average or larger person needs 61 to 62 inches of shoulder girth, and that extra inch or two makes a big difference. Using this technique, I can sleep warm in a 30F rated sleeping bag when the temperature drops into the 20s, assuming an adequate shelter to minimize convective heat losses.


I chose the size Long Flume UL 30 bag for it 62-inch shoulder girth (size Regular has 60 inches of girth). The extra length also makes it easier to enter/exit the bag and pull the hood over my head.

The Flume UL 30 contains 12 ounces of 850 fill-Power down in size Regular and 14 ounces in Size Long. The fill weight is a good way to compare sleeping bags, and 12 oz (Regular) or 14 oz (Long) is pretty decent for a 30F rated bag.

Insotect Flow construction claims the following advantages: 1) it holds down in place with fewer, smaller baffles; 2) it allows vertical baffles that contour to the body, holding insulation closer to the sleeper, and 3) it distributes body heat through the length of the bag. Using this construction method, the bag can be “body mapped” to place more down where it is needed (like the topside) and less down where it isn’t (like the bottomside). I have tested bags with “continuous baffles” that allow the user to shift the down as desired, which is good, but requires constant attention to avoid cold spots.

The Flume UL 30 has vertical baffles using Insotect Flow construction.

For an ultralight sleeping bag, the Big Agnes Flume UL 30 is feature rich (see specifications above), which perhaps adds 2 to 3 ounces to bag weight compared to a more minimalist bag. However, in my opinion, those details translate into more warmth, reliability, and convenience.

Big Agnes does not provide detailed specifications on the bag’s shell and lining fabric other than “ultralight high-tenacity ripstop nylon”. It appears to be equivalent to Pertex Quantum GL in terms of denier and downproofness.

Many manufacturers opt to put a full-length zipper on an ultralight bag, bowing to the notion that buyers insist on it, but Big Agnes seems to focus more on warmth and functionality. Rather than a long #3 zipper, Big Agnes uses a shorter more robust #5 zipper with a well-defined zipper track. The result is adequate zipper length for convenient entry/exit, more warmth, and little zipper snagging. The downside is the bag can’t be used as a blanket as easily on warmer nights.


I tested the Flume UL 30 bag on several summer mountain backpacking trips and one fall desert trip. Most nights the nighttime temperatures neared the bag’s temperature rating. The photo above was taken after a very damp night caused by an evening rain followed by a clear night and large temperature drop. The outer shell of the bag was coated with heavy condensation, but the bag’s DWR and water-resistant down kept it perfectly dry inside.

Ergonomically, the bag suits me just fine. I did not find any inconvenience with the shorter zipper; I entered the bag by sitting near the hood, bending my knees to slip my legs in, then sliding to my sleeping position.

The bag’s 62-inch girth provides plenty of room to wear camp clothing inside the bag to extend it s warmth, which is a must-have for me.

I had few problems with zipper snagging, owing to the bag’s roominess and zipper track design. While a tight-fitting bag puts stress on the zipper, causing it to lock or snag, a roomier bag allows the zipper to slide unimpeded. It does help to straighten the zipper channel with one hand while zipping with the other. One negative is the zipper will separate if it is unzipped all the way to the end, and it is frustrating to restart the zipper in the dark. I learned to stop zipping 1 to 2 inches before the end.

Sleeping bag warmth is very difficult to assess because it’s the composite of numerous variables. Wearing long johns, wool socks, and an ultralight down jacket inside, I found the Flume UL 30 to be warm down to its claimed 30F rating, which is actually a favorable evaluation, because most sleeping bags are optimistically rated. For that reason, some outdoor writers recommend getting a 20F bag if you want to be warm at 30F, or getting a 10F bag if you want to be warm at 20F. My preference, instead of going to a heavier 20F bag, is to wear my camp clothing inside the bag. That’s more versatile, because I wear the insulated clothing to stay warm in camp, and wear it in my bag to extend its warmth, and eliminate the need for a bag liner.


An ultralight sleeping bag is a key component of an ultralight gear kit, and it’s expensive, so it’s very important to do thorough research before you buy. This is something you want to get right the first time; otherwise it’s expensive buyer’s remorse.

Researching down sleeping bags is more difficult than other gear items because information is often lacking and it’s hard to compare them on a uniform basis. Comparing them solely on the basis of bag weight is not a good idea, because you can end up with a cold, tight fitting bag. More important are fill weight (the amount of down in the bag), fill-power (the volume one ounce of down expands to, in cubic inches), and shoulder girth. Since down fill-power varies, for comparing bags it helps to multiply fill weight by fill power to get total fill volume. The shoulder girth issue is explained above.

I found the Big Agnes Flume UL 30 to be a cutting edge ultralight down bag designed for warmth. Its pricing is similar to other bags in its class, but the design features and details are a level above. It’s warm to its specified temperature if you wear a few clothes inside, which is something you probably want to do anyway. The only way to get a warmer bag in this weight class is to order a custom bag with overfill.

The weight of the Flume UL 30 is a bit higher than other ultralight 30F bags, but in its defense I note that I have tested 20F bags of the same weight that are not any warmer. A smidgeon of extra weight is okay, if that weight is put into features that enhance warmth and functionality. In that context, Big Agnes gets it right with the Flume UL 30.

Thursday, November 30, 2017

GEAR REVIEW: Patagonia Airshed Pullover (Windshirt)

By Will Rietveld

A windshirt is a wonderful hiking garment under the right conditions – cool, overcast, and windy. Any two of those factors together constitutes good windshirt conditions. And, indeed, a windshirt over a baselayer is often an ideal combination for hiking comfort, especially in the cool months and mountains.

Windshirt breathability isn’t talked about much. They are designed to resist wind, using tighly woven fabric, calendaring, and coatings as design features to provide the desired performance. With their new Airshed Pullover, Patagonia emphasizes the garment provides “a balance between wind protection and breathability”. Is that possible, and does it make a difference under hiking conditions?

The Patagonia Airshed Pullover (3.7 ounces, $119) “balances wind protection and breathability”. (Patagonia photo)

Specifications and Features

Patagonia (www.patagonia.com)
Airshed Pullover
Mfr. Weight 3.7 oz; measured weight men’s Large 3.65 oz
Body: 1.3-oz 20-denier 100% nylon mechanical stretch ripstop with a DWR finish. Hem and cuff panels: 4.2-oz 79% nylon/21% spandex jersey
14 in zipper, 1 zippered chest pocket (converts to stuff sack), stand up collar, raglan sleeves, elastic cuffs and hem, stretch fabric. Trim fit.


I tested the Airshed Pullover over an 8 month period that spanned three seasons, and 19 outdoor trips in a wide range of conditions. Photo taken at Capitol Reef National Park, Utah.

The soft and stretchy fabric used in the Airshed Pullover is the same as the shell fabric on Patagonia’s Nano-Air insulated jackets, which are in a new category called “breathable insulation”.

It’s claimed to have a trim fit, but I find the fit to be typical for a size Large, which is my normal choice (I’m 6’ tall, 165 pounds, and 34” sleeve length). It has enough room inside to fit over a thick baselayer or fleece top, and the sleeve length is spot on. For me, an excellent fit.

I read an earlier review of this pullover on a prominent lightweight backpacking website, that cited air permeability numbers for the Airshed Pullover in the 50 to 60 CFM range versus only 1 to 7 CFM for a conventional windshirt. Those numbers were obtained by the author from a manufacturer representative, and are not specifications normally provided by the manufacturers. The article boosted my expectations for the Airshed Pullover.

A quick fabric air permeability test can be done by putting your mouth to the fabric and sucking air through it. Applying that test, I found that the Patagonia Airshed Pullover has distinctly higher air permeability than the Montbell Tachyon Jacket (1.6 ounces) I used for comparison.

In my field testing I gathered some comparative data for the two garments by placing a Kestrel Model 4000 Weather Tracker inside the zippered garment and recording temperature and relative humidity at 10 second intervals during a 90 minute hike over undulating terrain. The garments were tested in early morning on cloudy days. The starting temperature inside the garments differed by about 10 degrees, and the starting inside RH differed by about 6 percent.


The temperature data show the inside temperature initially cooled as I started hiking in cooler air, then became fairly steady through the remainder of the hike. Adjusted for the initial temperature difference, the two garments maintained about the same inside temperature during the hike.

Relative humidity inside the Airshed Pullover increased during the first half of the hike, to a higher level than the Tachyon, then remained fairly steady at about 60 percent. RH inside the Tachyon increased slowly and modestly in the first third of the hike, then gradually declined. The data suggest that the Airshed Pullover held more water vapor inside, rather than exhaust it through the fabric.

These results are contrary to the air permeability numbers and my mouth test, which indicated that the Airshed Pullover should have better breathability and exhaust moisture vapor more readily. So why didn’t the Airshed Pullover perform better in my instrumented field test?


It’s important to note that I did not feel much difference in comfort between the two garments during my testing. Furthermore, in all the product testing I have done over the years, I have never found that fabric breathability alone has much of an effect on perceived comfort. A much bigger factor, by orders of magnitude, is ventilation – simply open the front zipper and exhaust the steam. It’s much easier, and reliable, to adjust the front zipper for thermoregulation. Fabric breathability is minor compared to ventilation.

But there’s a wild card in this windshirt equation, and it’s called the sun. The radiant heat from the sun trumps everything, including opening the front zipper. If the wind subsides while hiking on a sunny day, a windshirt gets too hot inside and it has to come off. A windshirt works great in the sun on a windy ridge or constantly windy conditions, but in variable conditions the windshirt is on and off repeatedly. The best conditions for a windshirt are constant cool, overcast, and windy.

The key points in this discussion are:
·         Ventilation is much more important for garment comfort than fabric breathability.
·         Weather conditions have a larger effect on garment comfort than ventilation.


The Patagonia Airshed Pullover is a very nice windshirt, but don’t expect its breathability claim to be a silver bullet. It’s an analogous situation to Gore-Tex; Gore-Tex first needs to be waterproof, then it provides breathability (not much). Similarly the Airshed needs to be wind resistant, then provide some breathability (not much). During my many outings wearing the Airshed, I looked for extended comfort while hiking after the wind stopped and the sun came out, and didn’t find any. It got too hot to wear and I had to take it off, just like any other windshirt.

My recommendation is to select a windshirt that has a full height front zipper so you can open the zipper as needed for thermoregulation. My personal preference is an ultralight windshirt, like the Montbell Tachyon Jacket (1.6 ounces), so it’s a no-brainer to keep it in your pack. However, many hikers love the Patagonia windshirts because of their excellent fit and light jacket feel. Whatever you choose, get one with a full height zipper, and don’t get enamored by fabric breathability because there is not enough there to make a difference.