REASONS TO BUY
Unique frame offers ventilation and support
High-volume
Adjustable torso length and hip belt
REASONS TO AVOID
Very expensive
Lacks useful exterior pockets (optional)
Zpacks Arc Haul Ultra Review
It's hard to beat the comfort, support, and ventilation of this classic ultralight pack
The Zpacks Arc Haul Ultra is a classic ultralight pack with a frame that offers more support and ventilation than much heavier packs.
Credit: Justin Simoni
By Justin Simoni ⋅ Review Editor ⋅ June 10, 2026
RELATED: The Best Ultralight Backpack of 2026
Our Verdict
The Zpacks Arc Haul Ultra works hard to maximize comfort by providing superior back support and ventilation. Simultaneously, it's one of the lightest packs on the market, which is especially impressive considering its advertised 50-liter carrying capacity. Like many of Zpack's offerings, the Arc Haul is distinctively spartan in its design and features – so much so that you may want to add a few accessories to this already expensive pack. Its design is a little more complicated than other mainstream options, but once you dial in the adjustable fit, the added comfort will pay off big time for long days on the trail.
Compare to Similar Products
 This Product
Zpacks Arc Haul Ultra | |||||
|---|---|---|---|---|---|
| Awards |  Best Overall Ultralight Backpack |  Best Bang For Your Buck |  Best Full-Featured UL Pack | Best Pack for Expert Ultralighters | |
| Price | $399 List | $315 List | $279 List | $330 List Check Price at REI | $350 List |
Overall Score  |
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| Star Rating | |||||
| Bottom Line | It's hard to beat the comfort, support, and ventilation of this classic ultralight pack | This pack wowed us with its perfect set of features, comfortable design, and impressively large carrying capacity | A tough, voluminous, and reasonably priced ultralight backpack that's perfectly designed for long trips | An excellent pack for those who want to move up from a conventional backpack, but don't want to lose out on creature comforts | When it comes to frameless ultralight packs, this one leads the way in weight, design, and innovation |
| Rating Categories | Zpacks Arc Haul Ultra | Gossamer Gear Maripo... | Durston Kakwa 55 | Osprey Exos Pro 55 | Nashville Pack The C... |
| Comfort (40%) | |||||
| Ease of Use (25%) | |||||
| Weight-to-Volume Ratio (20%) | |||||
| Adjustability (15%) | |||||
| Specifications | Zpacks Arc Haul Ultra | Gossamer Gear Maripo... | Durston Kakwa 55 | Osprey Exos Pro 55 | Nashville Pack The C... |
| Measured Weight | 21.8 oz | 34.3 oz | 31.0 oz | 33.2 oz | 22.0 oz |
| Stripped Weight | 17.9 oz | 18.0 oz | 27.5 oz | 30.4 oz | 17.3 oz |
| Advertised Volume | 50 L | 60 L | 70 L | 55 L | 40 L |
| Measured Volume (Main Compartment) | 35 L | 54 L | 55 L | 46 L | 43 L |
| Weight per Liter (Full Pack) | 0.44 oz/L | 0.57 oz/L | 0.44 oz/L | 0.60 oz/L | 0.40 oz/L |
| Sizes Available | Torso: Short, Medium, Tall, Hip Belt: S, M, L, XL |
Torso: S, M, L Hip Belt: S/M Curved (w/ S torso), M Straight (w/ M and L torso); other hip belts sold separately |
Torso: S, M, L Hip Belt S/M, M/L |
Torso: S/M, L/XL | Torso: 16', 18", 20" Hip Belt: S (28"-38"), M (32"-42"), L (26"-48") Should Straps: 16", 17.5", 19", 20.5" |
| Organization Compartments | Main compartment, center pocket, side pockets | Top flat zippered pocket, three total side pockets, center pocket, dual zippered pockets on hip belt, main compartment | Side pockets, side zipper pocket, center pocket, hip belt pockets, strap pockets, main compartment | Lid, mesh side pockets, center pocket, dual zippered pockets on hip belt, main compartment | Main compartment, center pocket, running vest-style pockets, back-entry bottom stash pocket |
| Hydration Compatible | No | Yes | No | Yes | No |
| Side Pocket 700ml Smartwater Capacity | 2 | 3 | 3 | 5 | Continuous wraparound pocket |
| Single Hip Belt Pocket Capacity | N/A | 6 Clif Bars | 10 Cliff Bars | 4 Clif Bars | N/A |
| Removable Frame and Hip Belt | No | Yes | No | No | Yes |
| Sternum Strap Whistle | No | Yes | No | Yes | No |
| BearVault BV500 Compatibility | OK | Good | Excellent | Good | OK |
| Frame Type | Curved carbon fiber stays | Removable SitLight foam pad / removable stay | Removable foam pad / removable stay | 3.5 mm powder-coated LightWire frame | None |
| Fabric | Main body: Ultra 100X Center pocket: Nylon mesh Side pocket: Ultra 100X |
100D & 210D recycled Robic nylon | Challenge Ultra 200x | NanoFly: 100D nylon x 200D UHMWPE ripstop | 210D Venom Gridstop ECO |
Our Analysis and Test Results
Utilizing a water-resistant Ultra 100X-laminated material for its main pack fabric, as well as a very inventive and supportive sprung-back frame system, the Zpacks Arc Haul Ultra proves that ultralight does not have to be synonymous with uncomfortable. The frame design prioritizes ventilation while effectively transferring weight from your shoulders to the highly adjustable hip belt.
The Zpacks Arc Haul Ultra is an extremely capable, ultralight backpack. Credit: Justin Simoni
Likes
The Zpacks Arc Haul Ultra sets out to solve one of the biggest complaints amongst backpackers: a sweaty back! The backside of this pack features a highly breathable mesh liner that promotes airflow, whisking sweat away rather than trapping it between your back and the pack.
If a framed pack is sacrosanct, then this one should be at the top of your list. The combination of a very stiff frame, load lifters, and a firmly attached hip belt effectively transfers much of the weight onto your hips, allowing you to carry the pack more comfortably.
With plenty of space between your back and the pack, the Arc Haul Ultra provides exceptional airflow. Credit: Justin Simoni
The curved frame rests only partially on the center of your back, with most of the contact on your shoulders and hips, which makes for a comfortable carry. Credit: Justin Simoni
Adjustability is another huge strength for the Arc Haul Ultra. Dual cinch strap adjusters on each side of the hip belt really help you dial in the fit. Our male tester doesn't have the most pronounced hips, but even he was still able to adjust the pack to suit his body type.
Dual cinches on each side of the hip belt help adjust this pack to effectively transfer weight from your shoulders to your hips. Credit: Justin Simoni
The 50-liter Arc Haul Ultra achieves an incredible weight-to-volume ratio of 0.44 oz/L, in part by using very lightweight, durable, water-resistant Challenge Ultra 100X laminated pack material for the main body.
Additionally, it keeps features pretty sparse – if you want things like shoulder or belt pouches, you'll have to purchase them separately as accessories.
We measured the internal volume of the main body at around 35 L. Credit: Justin Simoni
Dislikes
In the default configuration we tested, we relied heavily on the cavernous interior, but that meant taking the pack on and off more than we would have liked. You'll also have to take a bit of time to adjust this pack to fit properly; otherwise, you'll likely have a less-than-stellar experience on the trail.
The exterior center pocket is listed as 8 liters, but we were only able to fit 5 1-liter Smartwater bottles. The mesh isn't very stretchy, so we're not quite sure where this advertised number comes from.
The mesh center pocket isn't very stretchy, except for the top elastane cord. Credit: Justin Simoni
Even if it's not as much as advertised, 5 liters of external storage in this one pocket is still quite a lot. Credit: Justin Simoni
A few other features do make it possible to carry more gear externally, including a long top strap you could use to carry a bear canister in a pinch. However, Zpack again sells a better-designed “V Top Strap” that's actually designed for this purpose.
A BV 425 bear canister can be strapped with the single top strap, but you're better off with the V-strap. Alternatively, a canister will fit inside the pack. Credit: Justin Simoni
For all its adaptability, these accessories really start to add up on top of an already expensive backpack. While the Arc Haul Ultra is well-designed, it's certainly not well-featured – many other backpacks come with these standard features and cost significantly less.
With an optimized ultralight kit, you can likely fit most of your gear inside the Arc Haul Ultra. Otherwise, the accessory pockets really add up. Credit: Justin Simoni
Should You Buy the Zpacks Arc Haul Ultra?
The Arc Haul Ultra is one of the lightest, most comfortable framed backpacks on the market. Compared to other ultralight packs we tested, it's also remarkably adjustable. However, it's expensive, and given that all those useful accessories we discussed only add to the cost, it may be well outside your price range.
What Other Ultralight Backpacks Should You Consider?
The Osprey Exos Pro 55 is another lightweight, breathable frame pack, though its more conventional construction may deter some committed ultralight backpackers. The Outdoor Vitals CS40 Ultra offers a nice compromise between the Exos Pro 55 and the Arc Haul Ultra – it's comfortable and supportive yet simple.
—Justin Simoni
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