REASONS TO BUY
Ultralight yet burly materials
Superb back padding and frame system
Comfortably carry heavy loads
REASONS TO AVOID
Expensive
May be too many features for newer hikers
Ultralight Adventure Equipment Ultra Circuit Review
A near-perfect thru-hiking pack that blends ultralight principles with conventional features
Cruising the flanks of one of Colorado's high peaks with the ULA Ultra Circuit.
Credit: Justin Simoni
By Justin Simoni ⋅ Review Editor ⋅ June 10, 2026
RELATED: The Best Ultralight Backpack of 2026
Our Verdict
The Ultralight Adventure Equipment Ultra Circuit is a comfortable, high-capacity pack that you can design to meet your needs. ULA offers more sizing options than most brands, giving you the opportunity to choose between torso size, hip belt size, and even the type of shoulder, top, and bottom straps. Aside from the custom options, you'll be surprised by how many useful features are packed into this lightweight pack. As your base weight changes between resupplies, easy adjustments to the hip belt, shoulder straps, and load lifters improve comfort on the trail. While this may sound like a thru-hiker's dream, all of this customization makes for an expensive pack.
Compare to Similar Products
 This Product
Ultralight Adventure Equipment Ultra Circuit | |||||
|---|---|---|---|---|---|
| Awards |  Best Overall Ultralight Backpack |  Best Bang For Your Buck |  Best Full-Featured UL Pack | Best Pack for Expert Ultralighters | |
| Price | $380 List | $315 List | $279 List | $330 List Check Price at REI | $350 List |
Overall Score  |
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| Star Rating | |||||
| Bottom Line | A near-perfect thru-hiking pack that blends ultralight principles with conventional features | 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 | Adventure Equipment... | 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 | Adventure Equipment... | Gossamer Gear Maripo... | Durston Kakwa 55 | Osprey Exos Pro 55 | Nashville Pack The C... |
| Measured Weight | 35.9 oz | 34.3 oz | 31.0 oz | 33.2 oz | 22.0 oz |
| Stripped Weight | 24.2 oz | 18.0 oz | 27.5 oz | 30.4 oz | 17.3 oz |
| Advertised Volume | 68 L | 60 L | 70 L | 55 L | 40 L |
| Measured Volume (Main Compartment) | 37 L | 54 L | 55 L | 46 L | 43 L |
| Weight per Liter (Full Pack) | 0.53 oz/L | 0.57 oz/L | 0.44 oz/L | 0.60 oz/L | 0.40 oz/L |
| Sizes Available | Torso: S, M, L, XL Hip Belt: XS, S, M, L, XL, XXL |
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 | Side pockets, center pocket, dual zippered pockets on hip belt, main compartment | 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 | 4 | 3 | 3 | 5 | Continuous wraparound pocket |
| Single Hip Belt Pocket Capacity | 5 Clif Bars | 6 Clif Bars | 10 Cliff Bars | 4 Clif Bars | N/A |
| Removable Frame and Hip Belt | Yes | Yes | No | No | Yes |
| Sternum Strap Whistle | No | Yes | No | Yes | No |
| BearVault BV500 Compatibility | Good | Good | Excellent | Good | OK |
| Frame Type | Foam pad, carbon fiber suspension hoop, and single aluminum stay | Removable SitLight foam pad / removable stay | Removable foam pad / removable stay | 3.5 mm powder-coated LightWire frame | None |
| Fabric | Ultra 400x, Ultra 200x | 100D & 210D recycled Robic nylon | Challenge Ultra 200x | NanoFly: 100D nylon x 200D UHMWPE ripstop | 210D Venom Gridstop ECO |
Our Analysis and Test Results
We measured the internal volume of the Ultra Circuit at around 37 L, with over 12 L in the side and center pockets. Opportunities to lash additional gear abound on the exterior if you need even more carrying capacity. The Ultra 200X, 400X, and UltraStretch materials are known for their durability, all but guaranteeing this pack won't fail halfway through your cross-country adventure.
The Ultra Circuit is one of our favorite adventure packs for high-alpine adventures. Credit: Justin Simoni
Product Updates
Since we last tested the Ultra Circuit, the product has been updated with a few new minor features that aren't fully reflected in our review:
- Ice axe and trekking pole loops are now both standard features
- Additional low-profile gear loops on the top and bottom of the pack to attach more gear
- "Y-strap" is now an option at checkout to complement the “Single” top strap option
Likes
Unlike many other ultralight packs, the Ultra Circuit features a breathable mesh back, foam back padding, a carbon fiber hoop, and a single aluminum stay. Padded shoulder straps, a removable padded hip belt, and load lifters all make for a comfortable carry up to the 35-pound load limit.
The Ultra Circuit is particularly adjustable. Options at the time of order include torso size, shoulder strap shape, hip belt size, and top and bottom strap styles. If that is not enough, Ultralight Adventure Equipment offers additional options to create a fully bespoke Circuit pack to your exact specifications (of course, at a higher cost and with a longer lead time).
The removable hip belt comes in sizes XS to XXL, fitting many different body types. Four points of adjustment are found on the belt itself. Credit: Justin Simoni
The frame stay and carbon hoop allow the load lifters to function well. Credit: Justin Simoni
Durability is at the forefront of pack design. The Ultra 200X pack fabric is one of the toughest materials for its weight. High-abrasion areas, such as the bottom of the pack and side pockets, use the even burlier Ultra 400X. Even the center pocket, which is usually a more delicate mesh, uses tough “UltraStretch” mesh instead.
We're so confident in the “UltraStretch” fabric used on the center pocket that we sometimes use it to stash snowshoes. Credit: Justin Simoni
If you want to simplify this pack, the hip belt, back padding, carbon fiber hoop, and aluminum stay are all removable, dropping the base weight down to 24.2 oz. If you need to bring additional gear for extra-long, extra-heavy carries, the Ultra Circuit has plenty of places to add shock cord to lash additional gear to the outside of the pack.
The ULA Ultra Circuit has a removable hip belt, suspension hoop and metal back stiffener. Credit: Justin Simoni
The hip belt is kept in place by a large swath of velcro, as well as two webbing straps. Credit: Justin Simoni
Shock cord is threaded on the front of the center pocket to stash easy to access gear. Credit: Justin Simoni
Dislikes
With so many creature comforts packed into the Ultra Circuit, it stands to reason that this pack won't be as lightweight as other, simpler packs. With all of its accoutrements, this pack weighs 35.9 oz. With an internal volume of 37 L, the base weight relative to the carrying capacity is good, but not great.
The manufacturer advertises this pack with a total capacity of 68 L, which is slightly optimistic. However, it does offer an impressive amount of storage outside of the main, internal compartment. The exterior center pocket easily holds six 1-liter Smartwater bottles, and each side pocket can hold three. The two hip belt pockets hold five Clif bars each. The Ultra Circuit compares directly to other 55-liter packs we tested.
The center pocket fits at least six 1-liter Smartwater bottles. Credit: Justin Simoni
Both side pockets tightly fit three 1-liter Smartwater bottles. Credit: Justin Simoni
Should You Buy the Ultralight Adventure Equipment Ultra Circuit?
With so many ways to customize this pack, the Ultra Circuit is designed for experienced hikers who know exactly what they want. Almost everything you could want from a high-capacity pack is on offer, but these options will add to the pack's base weight. Additionally, all of this customization makes the Ultra Circuit an expensive ultralight pack. Most people switching over from a conventional backpack will likely be better served with a different pack altogether.
The ultra-capable Ultra Circuit has taken us to some far-flung places! Credit: Justin Simoni
What Other Ultralight Backpacks Should You Consider?
The Black Diamond Beta Light 45 offers the same modularity, comfort, and durability as the Ultra Circuit, but in a streamlined package that won't leave you guessing about options. However, both of these packs are expensive. For a simpler, less expensive pack that doesn't sacrifice comfort or carrying capacity, check out the Durston Kakwa 55.
—Justin Simoni
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