Zpacks Arc Haul Ultra 50L Ultralight Backpacking Backpack Review
October 22nd, 2025
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Our verdict
We've used the Zpacks Arc Haul Ultra backpacking backpack for thousands of miles on thru-hikes across the world and in different climates and seasons. From desert to alpine, coast to forest, the Arc Haul has become one of our go-to packs for its lightweight, carbon fiber frame, and generous carrying capacity.
This minimal pack has a comfortable carry that can handle bigger loading capacities, while still boasting a nearly 1-pound weight empty. It is the lightest full-frame pack made with premium materials and is an excellent choice for ultralight backpackers who are serious about their gear.
The Arc Haul can carry 30-35 pounds comfortably, so it works well for heavy water carries on desert trails or routes, or longer food carries on long stretches of trail in wilderness.
The Arc Haul is best for thru-hikers, ultralight backpacking, and people undertaking long distance trails where you want an ultralight pack around 1 pound, but don't want to sacrifice durability or comfort. Made with Ultra 100X UHMPWPE fabric, we've found it handles bushwhacks, spiky desert plants, narrow canyons, and coast and desert sand.
We tested the Arc Haul on thru-hikes of the Arizona Trail and West Coast Trail, as well as backpacking trips in Yosemite and High Sierra. In all, we've spent nearly four months backpacking with this pack in temperatures ranging from 20°F to 104°F, in intense sun, wind, and rain. We've carried it on overnighters 2 miles from the trailhead to thru-hikes where we covered up to nearly 40 miles in a day.
The Arc Haul is best for thru-hikers or ultralight backpackers who have refined their gear system. We recommend this for a backpacker who has figured out their ultralight system and wants something that can handle weight well (i.e., isn't frameless) and is more durable.
Zpacks Arc Haul Ultra 50L
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Zpacks Arc Haul 50L Ultra backpack specifications
Weight: 22.3 oz (men's medium torso, medium belt), 21.8 (women's medium torso, medium belt)
Capacity: 50L total (37L main, 8L mesh pocket, 2.5L each side pocket)
Load Capacity: 30-35 lbs comfortable, 40 lbs maximum
Frame: Curved carbon fiber Arc Frame with suspended mesh back panel
Materials: Ultra 100X UHMWPE fabric (3.3 oz/sqyd)
Dimensions: 6.5" x 12.5" x 29" (16.5 cm x 31.8 cm x 74 cm)
Frame Heights: Short 17", Medium 20", Tall 23"
Best for: Thru-hiking, ultralight backpacking, long-distance trails
Warranty: 2-year limited warranty
Price: $399 (base model)
Note: the listed specs are for the 50L version, which is the volume we tested. It is also available in 40L, 60L, and 70L versions. For a full look at the specs for different volumes see our table comparing their capacities.
Comparison table
| BACKPACKING BACKPACK | MSRP | VOLUME (L) | MATERIALS | WEIGHT (lbs) | MAX LOAD (lbs) |
|---|---|---|---|---|---|
| Zpacks Arc Haul Ultra 50L | $400 | 50 | Ultra 100, Ultra 200, mesh, 3D spacer mesh | 1.4 | 40 |
| Zpacks Arc Haul Ultra 60L | $400 | 60 | Ultra 100, Ultra 200, mesh, 3D spacer mesh | 1.4 | 40 |
| Six Moon Designs Swift X | $375 | 56 | LiteSkin LS21 or EPX 200 | 2.4 | 35 |
| Gossamer Gear Mariposa | $315 | 60 | 100 & 200 denier Robic high-tensil strength nylon | 2.0 | 35 |
| Hyperlite Mountain Gear Junction | $379 | 40, 55 | DCH50 (main body) and DCH 150 (bottom), or DCH150 | White: 1.9 Black: 2.0 | 40 |
Who is it for?
The author wore the Zpacks ArcHaul on a thru-hike of the West Coast Trail on Vancouver Island, British Columbia in Canada.
Committed ultralight backpackers seeking maximum weight savings with frame support
Thru-hikers tackling long-distance trails (AT, PCT, CDT) with resupply strategies
Experienced hikers with refined ultralight gear systems and low base weights
Backpackers prioritizing ventilation and load transfer over maximum padding
Those wanting customizable fit with adjustable torso and interchangeable components
Weight-conscious adventurers willing to pay premium prices for cutting-edge materials
How we tested
Testing the Zpacks Arc Haul pack on the Grand Enchantment Trail, an off-trail route in Arizona and New Mexico. Photo by Kate Hoch.
We tested the Zpacks Arc Haul Ultra backpack on thru-hikes, backpacking trips, and quick overnighters across the world, including the:
Arizona Trail thru-hike 800-mile hike ranging from 9,000+ feet to TK feet in temperatures from 20F to 104F
West Coast Trail thru-hike on the wet coast of Vancouver Island, British Columbia on beach, bluffs, and through temperate rain forest and bogs
A 200-mile section hike of the Grand Enchantment Trail in New Mexico
Overnight trips in the San Gabriel mountains
Multi-day backpacking trips in Yosemite, Mammoth Lakes, and the Eastern Sierra
On each trip, we evaluated the pack for comfort, ease of carry, ease of packing and organization, and durability. Depending on the weather, we also tested for waterproofing, water resistance, and ventilation.
What we liked
The carbon frame on the Zpacks Arc Haul curves to the shape of your back while also remaining lightweight. Photo by Kate Hoch.
Carbon fiber frame and load lifters offer comfort and ease of carry compared to frameless or other ultralight lightly framed packs – both features are rare in near 1-pound backpacks
Durable and waterproof Ultra 100X UHMWPE fabric can handle nearly anything
Ability to choose between straight or curved shoulder straps, depending on how your shoulders and body are shaped
Waterproof Ultra 100X UHMWPE fabric with fully taped seams makes it nearly waterproof
Waterproof fabric doesn't absorb water
Patented adjustable torso system means you can dial in the torso length to exactly your size instead of settling for a S/M/L sizing system
Removable and interchangeable padded hip belts in multiple sizes allow you to switch out if you lose weight during a thru-hike
Unlike a lot of cottage ultralight backpacking gear, the wait time for this pack is minimal, and it ships in days
Made in USA
What could be better
Expensive, even for Ultra or DCF backpacking backpacks
Unlike other cottage, ultralight backpacking brands working in Ultra, not available in as many colors, patterns, or customizable designs
Must pay extra for shoulder strap pockets and hipbelt pockets, which sometimes come sewn in or included in other brands of ultralight backpacking packs
No women's-specific/curvy-body option for the hipbelt to better carry the load on the hips for women
Could have more padding in the shoulders and hipbelt
Back ventilation doesn't perform as well as we'd like
Mesh front pocket is not as durable as other mesh front pockets
Features
The suspension on the ArcHaul made the pack feel secure, even when scrambling, like this off-trail slot canyon section of the Grand Enchantment Trail. Photo by Kate Hoch.
Arc frame suspension system
The curved carbon fiber frame creates an air gap between the back and the pack for ventilation. While we've seen better ventilation on Osprey packs with similar designs, the support and comfortable carry that the curved carbon fiber frame offers is the real star of this system. Though lightweight and minimal, the curved carbon fiber frame punches above its class, making 6L water carries more comfortable than would be expected.
The frame keeps this pack rigid and maintains shape even when not fully loaded, so you can't fold or store it as easily after hiking season as a frameless pack. I've got mine hanging on the wall. The suspended mesh back panel supposedly prevents gear from poking into the back, but the thick Ultra 100X UHMWPE fabric likely is the real reason why you don't feel anything. The whole system is part of a patented design (US Patent No. 9,060,590) unique to Zpacks.
Part of the reason is that the Arc Haul transfers weight directly from shoulder straps to the hip belt for some of the better load distribution we've seen from an ultralight pack. Many ultralight backpackers who want a near 1-pound backpack might not want a hipbelt. But for those who know they'll be carrying heavier loads occasionally, the distribution of the weight is excellent on this pack.
Like many women, my center of gravity is lower, and I've experienced shoulder pain with other ultralight packs that don't distribute weight to the hips as well. This hasn't been an issue with the Arc Haul.
Also, if you're "not a hipbelt kind of person," the hipbelt isn't sewn in and is easily removable.
Ultra 100X fabric construction
The Ultra fabric on the pack makes it waterproof during this unexpected torrential rainstorm on the Arizona Trail near the Utah border.
The Arc Haul is made of Ultra High Molecular Weight Polyethylene (UHMWPE), which is stronger than steel by weight. This fabric is used by many cottage ultralight manufacturers and is more durable and arguably more affordable than Dyneema Cuben Fiber (DCF), which the brand used previously. It has a waterproof laminated backing that eliminates the need for DWR coatings, so it is PFAS free.
Ultra UHMWPE has extremely high abrasion and tear resistance. Seriously, the durability of this pack (and other Ultra UHMWPE packs we've tested) has surprised us with how solid this material is.
A major plus over almost every other ultralight pack we tested is the waterproofness of this pack. All seams and attachment points are taped for water resistance. Ultra UHMWPE is also waterproof .
Customizable fit system
The Zpacks Arc Haul uses a patented adjustable torso height system (US Patent No. 9,848,687) that helps you dial in the exact fit you want. With other packs, you often have to settle for the closest size.
The Arc Haul has interchangeable shoulder straps. You can choose between standard and Small/Women's options, which are more curved. They aren't sewn in, so if you lent a pack to a friend, you could theoretically switch out the straps.
One feature we really like is the removable and interchangeable padded hip belts in multiple sizes. Many thru-hikers find they lose weight over a 2,000+ mile hike, and with packs that have sewn-in hip belts, they find the hipbelt on their old pack no longer fits. This interchangeable hip belt system means you can just buy a different size hip belt as your body shape and size fluctuate between hiking seasons.
The hip belt features a unique kind of webbing system that we haven't seen on a lot of packs, called a "V-style" belt webbing. This supposedly allows a more precise fit adjustment, though we haven't noticed much of a difference compared to other packs.
The Zpacks Arc Haul notably has load lifter straps, which are a rarity among near 1-pound packs. Load lifters are a backpack design feature often found in 2-4 pound backpacks to fine-tune fit and reduce long-term shoulder pain from carrying a pack. If you've seen an ultralight backpacker with a pack that hangs uncomfortably off their back, chances are they would benefit from some load lifters. The Arc Haul's load lifters keep the weight of the pack close to your back to reduce the effort needed to carry the weight over time.
Like most packs, it has an adjustable sternum strap for fine-tuning fit.
Storage and organization
The Zpacks Arc Haul loaded with a 6 L water carry on the Grand Enchantment Trail. Photo by Kate Hoch.
The Arc Haul has a roll-top closure with compression, so you can use this pack on quick overnighters or longer carries where you can really load it up high above your head.
It has a large stretchy mesh front pocket for quick-access items and drying out wet gear or segregating it and storing it separately. Zpacks doesn't have my favorite mesh of ultralight pack companies, but it is certainly workable.
The two side pockets are positioned low and angled forward for easy access. They each can fit two 1L Smartwater bottles. It also has drainage holes in the side pockets to prevent water accumulation.
The Arc Haul has side compression cords for storing trekking poles and umbrellas without causing them to flop around.
Modular accessory system
The author relied heavily on the Zpacks shoulder pouch during her thru-hike of the Arizona Trail.
The Zpacks Arc Haul doesn't come with a lot of pockets, but there is an extensive selection of add-on accessories for customization:
HitchPoint attachment points throughout the pack
Compatible with hip belt pouches
Shoulder pouches and water bottle sleeves. It comes with daisy chains on the shoulder straps for attaching gear, but you have to buy the shoulder pouches and sleeves separately.
Additionally, many of the straps and components, like the hip belt, can be removed to get your pack's weight down even lower.
Each of these pockets is sold separately, which will start adding up the end price. However, if you already have a third-party shoulder pouch that you like, such as those made by CTUG, you can pop it off your other packs and use it on this one.
Bear Canister
The Zpacks Arc Haul will fit a bear can. It fits all standard bear cans vertically in the upper half of the pack. Zpacks recommends using a foam sit pad or clothing to fill out empty space and reduce the chances you'll feel the edges against your pack. I typically carry the super minimal Bare Boxer Contender when I have to use bear cans and can fit it in the bottom of the pack with no problem.
Carry on
I refuse to ever check-in my backpacking backpack on flights. I've traveled more than ten flights with this pack at this point and have had no issues carrying it on, other than the water bottle falling out as I load it into the overhead bin. For dedicated travel packs, see our Adventure Travel Backpacks guide.
Performance in the field
The Zpacks Arc Haul carried weight well, even on sections of the West Coast Trail that were vertical ladders.
Weight carrying
We've carried the Arc Haul on a thru-hike of the 800-mile long Arizona Trail and found that it has excellent load transfer up to 35 lbs and is tolerable to 40 lbs maximum. We often found ourselves carrying 6 L of water, and the Arc Haul had no problem doing that.
Ventilation
The Arc Haul's pack panel can help on hot days to increase ventilation. Photo by Kate Hoch.
In our opinion, every ultralight backpacking backpack will leave you with a sweaty back. We tested this pack on the Arizona Trail in 100°F+ temperatures, and the ventilation system on the Arc Haul did not keep us from having a sweaty back. That being said, we carried it in much milder conditions on the West Coast Trail, and the airflow with the suspended back panel design seemed to keep us fairly dry in the back. To be fair, we've never tested a backpack that completely prevents a sweaty back.
Durability
In testing, the author took this pack through almost 1,000 miles of spiky plants, slot canyons, or off-trail routes. Photo by Kate Hoch.
Ultra fabric on this pack is highly resistant to abrasion and tears. We've crawled under hundreds of blowdowns, tossed it through barbed wire fences, scraped it across Sierra granite, and accidentally placed it on spiky plants. Like all ultralight gear, we recommend cultivating a practice of babying it and not throwing it around. But on the off chance you find yourself in a situation where touching your pack near sharp and abrasive plants or rocks is inevitable, the Ultra UHMPWPE is impressive.
Fit customization
The Zpacks Arc Haul can really help you dial in fit better than what we've seen on other packs. The patented torso length adjustment means you can get your torso fit to be just right. As someone whose torso is on the edge between S and M, I appreciate being able to crank this up or dial it down to just the size I need.
Water resistance
The Zpacks Arc Haul excelled on the West Coast Trail on Vancouver Island, one of the wettest places in Canada. Photo by Kate Hoch.
While we still use a pack liner with the Arc Haul, we felt a lot safer carrying this pack on wetter thru-hikes, such as the notoriously wet West Coast Trail on Vancouver Island in British Columbia. Fewer ultralight brands are using the term "waterproof" because it has a very specific legal definition, but we found the Arc Haul to meet what we were looking for in terms of waterproofing. Zpacks recommends using a pack liner for your sleeping bag. I just use a trash compactor bag for the whole inside of the pack and have never had water intrusion with that system.
Zpacks Arc Haul vs. similar packs
The Zpacks Arc Haul Ultra has better fit, adjustability, and modularity than similar ultralight packs on the market. However, it is on the more expensive side of ultralight packs available, especially when considering the add-on costs of extras like shoulder pockets.
The carbon fiber curved frame and load lifters make it a lot more comfortable than the Hyperlite Mountain Gear Southwest 55. You have better color options and customization options on the Arc Haul than the HMG pack as well.
The Ultra fabric is more waterproof and durable than the Granite Gear Crown2 60 or Gossamer Gear Mariposa 60. The Mariposa has more padding and has a higher capacity (despite the similar stated volumes). We think the Mariposa is a better option for people who want comfort or are buying their first ultralight pack or going on their first long distance hike.
The Arc Haul is lighter weight than the ULA Circuit in Ultra. But the two have a lot in common, such as Ultra fabric and a comfortable load-carrying system. ULA has some better color and pattern customization options.
We also find better customization, color, and pattern options on the LiteAF Full Suspension Curve pack. However, that pack is more expensive, and we find the load carrying better on the Zpacks, especially for folks with shorter torsos.
Ultimately, the Zpacks Arc Haul Ultra is a good choice for someone who has their ultralight system dialed in and wants a pack that has just the features and fit they need.
Other Capacities Available
The ArcHaul is available in four capacities, all of which are the same price. You can decide which is the best for you based on the length of your trip, your food and water carry needs, and other gear you may need to carry (such as cold weather gear or dog gear).
| BACKPACK | MSRP* (BASE) | WEIGHT (MEN'S) | WEIGHT (WOMEN'S) | VOLUME | LOAD |
|---|---|---|---|---|---|
| Zpacks Arc Haul Ultra 50 L Men's Women's |
$399 | 22.3 oz | 21.8 oz | 50 L | 30-35 lbs., 40 max |
| Zpacks Arc Haul Ultra 40 L Men's Women's |
$399 | 21.9 oz | 21.4 oz | 40 L | 30-35 lbs., 40 max |
| Zpacks Arc Haul Ultra 60 L Men's Women's |
$399 | 22.6 oz | 22.2 oz | 60 L | 30-35 lbs., 40 max |
| Zpacks Arc Haul Ultra 70 L Men's Women's |
$399 | 23.0 oz | 22.6 oz | 70 L | 30-35 lbs., 40 max |
Should I buy the Zpacks Arc Haul Ultra?
Buy if you're a serious ultralight backpacker seeking the lightest full-frame pack with premium materials and don't mind the high price.
Skip if you're new to ultralight backpacking, prefer traditional padding/comfort, or need hip belt pockets without paying extra.
Where to buy the Zpacks Arc Haul Ultra?
As a small, made in the USA brand, the Zpacks Arc Haul Ultra can only be purchased on the Zpacks website.
Similar products
LiteAF Full Suspension Curve pack
Capacity: 55L or 61L
Weight: 25 to 36+ ounces, depending on fabric, size, and add-ons
Max load: 35 lbs
Cost: $330-$620
The LiteAF Full Suspension Curve pack has a lot in common with the Zpacks Arc Haul Ultra, including the use of Ultra fabric and a lightweight, carbon frame, and both are made in the USA. The LiteAF weighs slightly more and is more expensive.
The LiteAF Full Suspension Curve pack has a narrower and longer profile, kind of like a bullet. Like with the Arc Haul, you can choose hip belt sizes, but we find that the hip belt doesn't curve around the hips as well on the LiteAF, which especially bothered women's testers. The LiteAF has undeniably better colors, patterns, and designs than the Zpacks Arc Haul. The lead time before shipping on LiteAF can be longer, especially if you're getting a custom design.
The LiteAF Full Suspension Curve is our pick for Best Thru-Hiking Backpack in our Best Lightweight Backpacking Backpacks guide. Learn more in our in-depth review of the LiteAF Full Suspension Curve Backpacking Backpack.
LiteAF Full Suspension Curve pack
Capacity: 60 L
Weight: 2.0 lbs
Max load: 35 lbs
Cost: $315
The Gossamer Gear Mariposa is a classic lightweight backpacking backpack that has a lightweight frame and is popular with thru-hikers. The Zpacks Arc Haul Ultra is made of a waterproof and seam taped Ultra 100X UHMWPE fabric that is more durable and certainly more waterproof than the Robic used in the Mariposa.
Despite the similarly stated volumes of 55L and 60L, the Mariposa can fit a lot more than the Arc Haul. That makes it a better option for when you're figuring out your ultralight system, what you like to carry, and how you like to carry it. The Mariposa is a more forgiving pack and won't cause as many injuries or as much pain if you don't do things quite right. You can watch our video about how stated volumes different in backpacking backpacks.
Ultimately, the Mariposa is a better option for the first lightweight backpacking backpack, but the Arc Haul is a better option for when you're willing to spend more money and have your ultralight system dialed in.
The Mariposa is our pick for backpackers who want to try ultralight backpacking. Learn more in our in-depth review of the Gossamer Gear Mariposa Backpacking Backpack.
Gossamer Gear Mariposa
Capacity: 50 L
Weight: White: 1.9, Black: 2
Max load: 40 lbs
Cost: $379
The Hyperlite Mountain Gear Southwest 55 is an ultralight backpack with a 55L capacity and is constructed of Dyneema Composite Hybrid. The white has 50-denier Dyneema, weighs 31.7 oz, and costs $379. The black version of the 55L is constructed of the much more durable 150D Dyneema. The black 55L weighs 34.6 oz and costs $399. Pockets on the shoulder straps cost extra.
W also done a long-term review of the similar Hyperlite Mountain Gear Junction (40 or 55L) pack. Be sure to read that full review if you are looking for another Hyperlite pack comparison.
Hyperlite Mountain Gear Southwest 55
Osprey Exos/Eja 55 Pro
Capacity: 58L
Weight: 2.65 lbs
Max load: 30 lbs
Cost: $320
The Osprey Exos 55 Pro (large) has 58 L of volume and weighs 35 oz. The Eja has 55 L of volume and weighs 33 oz. Both packs are constructed of 100D nylon and cost $290. We find the Robic material on the Mariposa to be more durable than the Exos and Eja.
The 55L volume on the Mariposa is also more generous than the Exos and Eja. In fact, in our tests (see below on a note about backpack comparisons), the Mariposa was more like 70L. The ventilation on the Eja is better. However, it isn't as customizable as the Mariposa. The Mariposa can be folded up and turned into a frameless pack but there is no way to remove the frame on the Exos and Eja.
Osprey Exos/Eja 55 Pro
Capacity: 68L
Weight: 33.8 oz
Price: $380+
Material: Ultra or Robic
ULA started selling their much-beloved Circuit backpack in Ultra fabric. The Circuit is a tried and true, extremely popular thru hiking backpack. Treeline Operations Coordinator Sara "Socks" Kruglinski has over 5,000 miles with a ULA Circuit – at times carrying 9 L of water or 10 days of food. You can read her full review of the ULA Circuit here.
ULA Ultra Circuit
Why you should trust us / About the author
Liz Thomas is an award-winning Los Angeles-based writer and Editor-in-Chief of Treeline Review. A former Fastest Known Time (FKT) record holder on the Appalachian Trail, Liz came to Treeline Review from New York Times/Wirecutter, the New York Times’ product review site, where she was a staff writer on the outdoor team.
She was a guest editor at Backpacker Magazine, where she is the columnist of “Ask a Thru-hiker” and instructor of their online class, Thru-hiking 101.
Liz has thru-hiked 20,000+ miles, always using ultralight packs like the Zpacks Arc Haul. To test the Zpacks Arc Haul Ultra, she's used the pack on more than 1000 miles of trails in temperatures ranging from 20F to 100F+. Her testing of this pack included a thru-hike of the Arizona Trail and West Coast Trail, as well as sections of the Pacific Crest Trail and Grand Enchantment Trail.
Her first book is Long Trails: Mastering the Art of the Thru-hike. The book was the recipient of the National Outdoor Book Award for Best Instructional Book, and was deemed by judges as destined to become the “Bible of the Sport.”
Liz has talked gear on Good Morning America (TV), in The Wall Street Journal, The Guardian, Buzzfeed, The Washington Post, Men’s Journal, Women’s Health, Gizmodo, and Outside Magazine.
She represented the sport of hiking at President Obama’s Great American Outdoors Initiative.
Liz’s keynote speaking engagements have included colleges and universities including Yale and MIT and on Capitol Hill, the Trust for Public Land, American Hiking Society, and BikeTexas.
You can read more about Liz at her wikipedia page here!
