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

Friday, September 23, 2016

GEAR REVIEW: ZPacks Duplex Tarp

By Will Rietveld

Many readers are already familiar with the popular ZPacks Duplex Tent, which is a Cuben Fiber 2-person single-wall trekking pole supported shelter with two doors and vestibules, a mesh entry and perimeter, and a bathtub floor. The weight is 20.7 ounces, which is amazing for a roomy 2-person shelter.

I was introduced to the Duplex Tent when two of my backpacking buddies got this shelter for one person. I was envious of its roominess, and impressed with its design and performance in rain and wind.

Then, when I visited the ZPacks website, I found something really interesting: ZPacks has another version of the Duplex available, the Duplex Tarp without any mesh or floor. Everything else is the same, except this version is meshless and floorless. The weight, according to ZPacks is 10.7 ounces for the shelter with guylines. That’s half the weight of the Duplex Tent (20.7 ounces).

The meshless, floorless Duplex Tarp weighs half as much as the Duplex Tent.

About that time my inner gram counter got really excited! The Duplex Tarp has a wonderful design and amazing roominess for just 10.7 ounces (the measured weight is actually 9.85 ounces, sans the mid-side guylines).

While many hikers won’t consider a floorless shelter, I happen to like floorless. There’s only one door to enter, more usable protected area inside, and it’s a good option if you hike with a dog. I usually camp above treeline where bugs are not a big issue, but I realize that excluding bugs and creepy crawlers is a major requirement for many hikers.

So how well did the Duplex Tarp meet my expectations? Read on to find out.

Specifications and Features

ZPacks (www.zpacks.com)
Duplex Tarp
Capacity and Style
2-person, 2 trekking pole supported, single-wall floorless shelter with 2 doors and vestibules
53 in wide (86.5 in wide including vestibules) x 100 in long x 48 in high
Measured weight 9.85 oz for shelter and 6 guylines; manufacturer specification 10.7 oz for shelter and 8 guylines
0.51 oz/sq yd Cuben Fiber
Guylines with Lineloks allow easy tensioning and adjustment of shelter height; 2 side entry doors with vestibules; door panels overlap, are secured with a toggle, and are extended with Dutchware Hooks; tensioned catenary ridgeline; 8 staking points with guylines and Lineloks, clothes line loops inside

Setup and Use

I particularly like the design of this shelter. It has two peaks supported by trekking poles, with a catenary ridgeline between them that is tensioned with guylines from the peaks to the ground. This gives the shelter a very taut and storm-resistant basic structure that is further strengthened by tensioning the corner and mid-wall guylines.

Sleepers are positioned perpendicular to the ridgeline and sloped walls; the entry doors and vestibules are at the sides of the shelter. That arrangement puts the sloped walls of the shelter just above your head and feet. It’s possible to sleep parallel to the ridgeline, but that puts your head and feet into the vestibules, and the trekking poles will divide two sleepers. For one person, which is a likely scenario for this shelter, there is unlimited space and sleeping options.

ZPacks lists the shelter’s dimensions as 53 inches wide, 100 inches long, and 48 inches high at the peaks. My measurements came out a little short on the length. I found that angling the poles out a bit provides a width up to 68 inches, but that extends into the vestibules a bit and reduces headroom. With trekking poles set to 48 inches as specified, and sloped walls pinned to the ground the measured length is 86 inches and height at the center is 42 inches; extending the corner guylines increased the length to 94 inches; lengthening the poles to 52 inches and further extending the corner guylines did not change the width but did increase the headroom at the center of the shelter to 46.5 inches. In summary: 1) the width can be increased a bit by angling the poles outward; 2) it is difficult to get the full specified 100 inches of length, but 86-94 inches is adequate; and 3) the specified height is at the peaks, which are about 4 inches higher than the center of the ridgeline.

Setup is simple and fast: 1) lay the shelter out in the desired location (preferably with the sloped sides facing the wind); 2) stake the four corners loosely, 3) insert the trekking poles (adjusted to about 48 inches) in the peak pockets and raise the tent (angle the bottom outward a bit to increase interior elbow room); 4) stake the guylines from the peaks; and 5) tension the guylines all around.

I found that a Gossamer Gear Polycro 2-person groundsheet (3.65 ounces) fits the Duplex perfectly, and is quite durable. It can be adapted to a “bathtub floor” by attaching a short piece of elastic cord and hooks to the corners of the groundsheet (reinforced with tape), which is then tied to the Lineloks at the corners of the shelter.  This arrangement needs to be designed to accommodate different pitch heights of the shelter.

The Duplex Tarp can be pitched at different heights, depending on weather and bug conditions. When it’s windy or breezy I like to stake the corners to the ground to reduce airflow through the shelter. A titanium shepherd-hook stake fits through a corner Linklok buckle as shown in the photo.

On a calm night, when more airflow is desired, the shelter can be pitched higher by extending the trekking poles and corner guylines.

The entry doors are a masterpiece of simplicity and functionality. There is no zipper; the doors overlap to seal, and a toggle & loop holds them closed.

The vestibule is extended out by a custom “Dutchware Hook” (left) that has two clips for D-rings at the bottom of the door panels to snap into. An integrated Linelok enables tensioning against the stake from the shelter’s peak (right). This arrangement nicely extends, tensions, and seals the vestibules; and either door can be opened fairly easily from the inside for egress.

The following videos provide tours of the outside and inside of the Duplex Tarp.


I tested the Duplex Tarp on several late summer backpacking trips in the Southwest Colorado Rockies, camping at higher elevations. I used it alone as a solo shelter and with my wife as a 2-person shelter. The weather varied from balmy to stormy with wind, rain, hail, and snow.

Although tent weights are typically given as the “trail weight” or “minimum weight”, it is often unclear what is included, which is frustrating. For the Duplex Tarp, the minimum weight of the shelter plus guylines, groundsheet, and six stakes is 14.9 ounces. I removed the guylines from the sloping walls of the tent, and use six shepherd hook stakes instead of the recommended eight. These ultralight stakes work quite well, if you put a rock on them.

As a 1-person shelter, the Duplex Tarp is hard to beat; it provides an enormous amount of protected area and excellent shelter from weather.

As a 2-person shelter, the 53-inch width of the Duplex Tarp provides adequate room for two sleepers plus gear; that’s more then you get in most tents. When the sloping walls are staked to the ground, the shelter has enough headroom so I don’t brush against the inside wall when I sit up, but that requires the footbox of my sleeping bag being against the opposite wall (I’m 6 feet tall).

When weather and bugs permit, the shelter can be pitched higher to get even more protected area inside. That’s usually a calm night when you want more air circulation through the tent to prevent condensation. I like to leave one or more door panels open at night, when conditions permit, for ventilation and easy entry/exit.

Since my testing was done in late summer, I didn’t have an opportunity to test the shelter’s bug-resistance. However, I note that even when the sloped walls of the shelter are staked to the ground, the vestibules are raised about 8 inches off the ground. That would allow insects to enter fairly easily, so a headnet may be necessary when camping with bugs.

The raised vestibules are also an issue when it’s windy. Although the best wind-resistance is achieved by orienting a vestibule into the wind, that orientation allows wind to enter under the vestibule and invade the interior. Orienting a sloped wall, staked to the ground, to the wind keeps the wind out better, but it makes the shelter more susceptible to strong gusts, and the shelter contorts more. Using the mid-wall guylines would help to deflect the wind.

On one early September backpacking trip we camped in a beautiful basin at 12,500 feet. It was sunny and windy the day we arrived, and stormy late that night extending into the morning. We didn’t have the shelter oriented right for good wind protection (described above), so it was breezy inside. However, the shelter provided excellent protection from rain, hail, and snow, as good as any tent we have tested.

One nice thing about a Cuben Fiber shelter is, once tensioned, the material does not absorb water and sag, requiring re-tensioning, as with a nylon fabric shelter.

And one thing to keep in mind when using a floorless shelter, is to choose a campsite with good drainage away from the shelter. When it’s raining, water often pools on a compacted campsite, and you don’t want that puddle inside the shelter! The same principle applies to a floored tent, but more so to a floorless shelter.


A floorless shelter is not for everyone and every situation, but if you are an experienced ultralight backpacker, and have camping conditions suitable for a floorless shelter, it is a great way to reduce weight and increase versatility. In the case of the ZPacks Duplex Tarp, you get all of the benefits of the well-designed Duplex for only half of the weight and about 60% of the cost.

Ten years ago, who would have thunk than an ultralight backpacker could include a 2-person shelter with two doors in a 6-pound Mountain SuperUltralight (M-SUL) gear kit. If you are not familiar with that term, read my series on M-SUL backpacking at www.Backpackinglight.com. The ZPacks Duplex Tarp (and many other trekking pole supported Cuben Fiber shelters) makes it possible to have a SuperUltraLight gear kit and also have a very roomy protective shelter. I personally like an enclosed shelter for a good night’s sleep. A shelter like this is also called an “enclosed tarp”, which may be more descriptive, but it is hard to keep from calling it a tent.

The Duplex Tarp is somewhat hidden on the Zpacks website; you need to click on the Duplex Tent, and down a ways there are a pair of configuration/pricing gadgets, the right one showing the Tarp option. It was a lightbulb moment for me when I found it, because I realized I could get a Duplex for half the weight and 60% of the cost; compared to $599 (pricey) for the Tent, the Tarp costs $375 (a great value for a Cuben Fiber shelter).

From my 15 years of experience as a gear tester and reviewer, formerly with Backpacking Light magazine and now freelancing on my own, and having tested numerous shelters over the years, I can confidently state that the ZPacks Duplex Tarp is my current favorite. It’s a sturdy design, well-constructed, user-friendly, and very versatile and functional for ultralight backpacking. You need to be an ultralight backpacker, place a high priority on light weight and functionality, and have the appropriate situation, to fully appreciate the Duplex Tarp. For a M-SUL backpacker, it’s a great find.


  1. Thanks for the review. Very tempted to buy one (I own the Zpacks Hexamid Solo w. bugscreen, but the Duplex provide much more space, liveability and stormworthyness). Always a pleasure to read your thorough reviews. Greetings from Denmark. - Terje

  2. It's a good choice. I previously used the Hexamid Twin for several years. I liked it, but I like the Duplex Tarp better for the reasons you mention.

  3. It's a good choice. I previously used the Hexamid Twin for several years. I liked it, but I like the Duplex Tarp better for the reasons you mention.

  4. Do feel that the Hexamid Solo version of the tarp would be good enough to deal with the mosquitoes in Colorado? I don't often have problems with mosquitoes there. Mostly, during the day--can't recall a night with mosquitoes once the temps drop below 55 F or so.

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