Updated:
Jan 20, 2025Comfort
Organization
Weight
Durability
Water Resistance
Sustainability
Weight
2 lb. 6.5 oz.
Stated Load Limit
35 lb.
Fabric(s)
400D Robic nylon
Adjustable Torso
No
# of Pockets
5
Access
Top
Capacities
68L
Included rain cover
No
Pros
Cons
ULA Equipment Circuit
For this season's top models, see our guide to the Best Backpacking Backpacks.
I almost exclusively hike with frameless ultralight packs, but the ULA Circuit is one of the first I’ve been eager to test that includes an internal frame. While I was initially skeptical about straying from my frameless norm, this pack’s level of support shocked me—in a good way. Across multiple backpacking trips in southwest Texas and the New Mexico badlands—each requiring me to carry extra water given the desert conditions—I carried up to 35 pounds comfortably in the Circuit.
The Circuit’s impressive carrying capacity comes courtesy of a robust, multi-part suspension, consisting of a hard foam framesheet, a carbon-fiber-and-hard-plastic hoop, and an aluminum stay. I immediately noticed that the frame changed how the Circuit rode compared to the body-hugging feel of a frameless pack. Rather than sagging on my shoulders, the Circuit more deftly distributed the load throughout my hips and torso, which made it feel like the weight was floating. This did throw off my balance a bit as the pack felt less like an extension of my body than what I’m used to, but it only took me a few miles to adapt, and the long-term comfort benefits were noticeable. The foam backpanel doesn’t offer the same no-holds-barred airflow that you get from a suspended mesh backpanel (like that of the Zpacks Arc Haul), but the ULA Equipment Circuit still provides an almost unbelievable amount of comfort for an ultralight backpacking pack.
Like most ultralight backpacking packs, the ULA Circuit forgoes a top lid and features roll-top access to the main compartment. The pack’s 68-liter volume is quite spacious, and should you not fill the entire space—as your load decreases over the course of a thru-hike, perhaps—the top rolls down to a compact size and straps on the pack’s side help compress the silhouette even further.
The rest of the storage is highly convenient and accessible from the outside of the pack. One of my favorite storage features was the two large zippered pockets on the hipbelt—I was pleased to find that I could stash three energy bars and a pack of gummies on one side and my sunscreen, shades, salt pills, chapstick, and extra batteries on the other. I was also able to fit my iPhone 15 Pro Max here once the energy bars were removed.
The Circuit has two hydration ports for a water reservoir hose—one on each side—but I chose to go with my trusty water bottle system. Two generous side pockets, made from the same durable 400-denier Robic nylon as the main pack body, can each accommodate two one-liter water bottles while still having enough room for items such as toiletries or trekking poles (these are built to fit an ultralight tent, too). A deep stretch mesh pocket covers most of the pack’s dorsal side, and a shock cord weaves across the mesh for extra storage and security. I found this pocket/cord combo incredibly secure and impressively durable, but the setup does make it difficult to reach into the pocket and find whatever I’m looking for. The pack also features ice axe loops on each bottom corner.
The Circuit in a size medium torso and hipbelt combo checks in at 2 pounds 6.5 ounces. To my surprise, even with its internal frame and convenient storage, it weighs less than the 70-liter Hyperlite Southwest pack I typically use. Add in its class-leading comfort and support, and the Circuit felt significantly lighter on my back than the Southwest. Staying within the ultralight world, Gossamer Gear’s Mariposa 60—another long-distance-focused pack with an internal frame—weighs 2 pounds 2.2 ounces with a medium torso and hipbelt and also easily carries up to 35 pounds.
For another comparison point, the ULA Equipment Circuit weighs about half a pound less than the Osprey Exos 58, which offers less storage space and about the same load capacity (35 lb.). But for the extra ounces, the Exos tacks on more shoulder and hipbelt padding, a breathable trampoline backpanel, and 4 inches of adjustability in the torso length. Finally—and while this comparison verges on the realm of apples to oranges—famously burly packs such as the Gregory Baltoro 65 and the Osprey Atmos AG 65 are about double the weight of the Circuit. Those models offer top-of-the-line comfort and robust suspensions and have an even higher load capacity, but they’re also more expensive and overkill for ultralight- or minimalist-minded backpackers.
Initially, I was skeptical about the Circuit’s ability to withstand rough-and-tumble trail conditions, due to its 400-denier Robic nylon material, which is significantly different from the Dyneema fabrics used in comparable ultralight packs. Overall, however, I’ve been impressed with this fabric: It’s much quieter and more flexible than Dyneema, and at this point, it’s held up to a month’s worth of testing with only one small puncture in one of the side mesh pockets. The mesh back pocket is made from thick material that stretches well with each item I put inside, and the stitching appears quite reliable. Overall, the Circuit’s quality makes it well worth its cost, which is less than ultralight models made with Dyneema.
While the ULA Circuit is not a waterproof backpacking pack, its nylon material is treated with a polyurethane coating as well as a durable water repellent (DWR). This design makes it highly water-resistant, and the pack body is able to withstand moderate rain without soaking through quickly. However, if heavy and extended rain is in the forecast, I’d recommend packing your gear in waterproof stuff sacks or purchasing a rain cover.
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Longevity
Choosing durable outdoor gear and keeping it in use for longer is one of the best ways to reduce environmental impact. Our proprietary longevity rating assesses factors like overall build quality, materials, fabric denier, component durability, and real-world performance. A green check indicates that we expect the product to be long-lasting relative to its peers, a yellow check mark indicates average longevity, and a red X indicates a product that may have a limited lifespan.
PFAS-Free DWR
Durable water-repellent (DWR) finishes can contain PFAS (per- and polyfluoroalkyl substances). These highly persistent “forever chemicals” are used in outdoor gear for their strong resistance to water, oil, and heat, but are linked to environmental contamination and a range of health concerns. A green check mark indicates the product uses a PFAS-free DWR, while a red X means the DWR contains PFAS.
Recycled Materials
Recycled materials are prevalent in outdoor gear, with nylon, polyester, wool, and down among the most common, but the composition varies widely. A green check mark indicates the product is made with a substantial amount of recycled materials (100% recycled or the core fabric that makes up most of the product is recycled), a yellow check means it contains a moderate to small amount of recycled materials, while a red X means there are no recycled materials in the product.
Bluesign Approved
Bluesign Technologies, based in Switzerland, operates a third-party textile management system that ensures materials are manufactured to strict environmental, chemical, and worker safety standards. A green check mark indicates a product is either a Bluesign Product (contains at least 90% Bluesign-approved fabrics and 20-30% Bluesign-approved accessories) or features a significant amount of Bluesign-approved materials. A yellow check mark means it uses some Bluesign-approved materials but less than the aforementioned category, and a red X means there are no Bluesign-approved materials in the product.
Responsible Manufacturing
This criterion evaluates a brand’s commitment to fair wages, safe working conditions, and reducing environmental impact through certifications and programs like Fair Trade Certified, Fair Wear Foundation, Worldwide Responsible Accredited Production (WRAP), and the Fair Labor Association, while also recognizing brands that manufacture primarily in the U.S. or Europe under strict labor and environmental regulations. A green check mark indicates a brand meets our responsible manufacturing criteria, while a red X means it does not.
Recycled and/or Reduced Packaging
Packaging can add significant waste to outdoor gear purchases, so many brands work to reduce its impact by using recycled materials, incorporating Forest Stewardship Council-certified paper products, and minimizing plastic and paper use. A green check mark indicates a brand uses recycled or reduced materials across all of its packaging, a yellow check indicates moderate or limited use of recycled or reduced packaging, and a red X indicates the brand does not make either of these efforts.
Repair Services
Repair services extend the lifespan of outdoor gear and reduce overall consumption, though programs vary widely. Some brands offer comprehensive repairs for a range of issues, while others provide limited or no repair support. A green check mark indicates a robust repair program, a yellow check mark indicates limited repair services, and a red X indicates the brand does not offer repair services.
Resale and/or Recycling Services
Resale and recycling programs help keep outdoor gear in circulation longer and out of landfills, ranging from trade-in resale platforms that offer store credit to take-back initiatives that recycle products at the end of their usable life. A green check mark indicates a brand offers both resale and recycling programs, a yellow check mark indicates it offers one or the two, and a red X indicates it offers neither.
Carbon Footprint Tracking
This criterion evaluates whether a brand measures, reports, and works to reduce its greenhouse gas emissions using established frameworks such as the Higg Index, Greenhouse Gas Protocol, or The Change Climate Project. A green check mark indicates a brand publicly reports greenhouse gas emissions data, sets clearly defined reduction targets, and uses established tracking frameworks such as Higg or The Change Climate Project. A yellow check mark indicates the brand tracks emissions and outlines reduction goals but provides limited data, lacks science-based verification, or does not clearly report progress. A red X indicates the brand does not appear to track greenhouse gas emissions or provides so little information that its efforts cannot be verified.
Annual Impact Report
Annual impact reports provide transparency and accountability by outlining a brand’s sustainability efforts across areas such as material sourcing, greenhouse gas emissions, waste, water use, supply chains, and packaging. A green check mark indicates a brand publishes a detailed, brand-specific impact report that closely aligns with our sustainability criteria and leaves little room for ambiguity. A yellow check indicates a brand provides some relevant sustainability reporting but lacks detail in key areas or is covered only briefly within a parent company report. A red X indicates a brand does not regularly publish an impact report.
Tester: 6’3”, 21” torso
Size tested: Large torso, XL hipbelt
ULA offers plenty of sizing customization options for the Circuit, with unisex torso sizes ranging from small to XL and hipbelt sizes from XS to XXL. I very much appreciated the bespoke fit, and the sizes I chose were spot on: The large torso was an ideal length for my torso size, and the XL hipbelt wrapped my hips perfectly. I also chose the “J-strap” shoulder straps made for hikers with broad shoulders, and ULA also offers the “S-strap” straps for those with standard or sloped shoulders. I do, however, wish that the ULA Equipment Circuit had more adjustments for the width between the shoulder straps, as I encountered quite a bit of rubbing from them against my neck.
Osprey Exos 58 ($285): More Comfort for the Masses
The Osprey Exos 58 (and women’s Eja 58) is a pack with ultralight sensibilities, but not true ultralight specs. It’s about 7 ounces heavier than the Circuit, which gets you more organization, fit adjustments, and overall comfort than the Circuit. Those used to traditional backpacking packs will appreciate the convenience of the Exos’ top lid, and a ladder adjustment on the torso affords 4 inches of torso adjustability. Plus, you get generously padded shoulder straps, a cushy hipbelt, and a trampoline-style backpanel that generates a nice, sweat-diminishing breeze across your back while protecting you from potentially pointy gear. The Exos is a bit heavy and overbuilt for serious thru-hikers, but if you’re new to ultralight packs and want a smoother ride, it’s a great option for $15 less than the Circuit. For more, read our review of the Osprey Exos 58.
Gossamer Gear Mariposa 60 ($315): A True Ultralight Competitor
Shaving off a few ounces (for a size medium torso and hipbelt), the Gossamer Gear Mariposa 60 is one of the Circuit’s closest competitors. Its classic ultralight pack design offers similar storage to the Circuit, but tacks on a streamlined top lid (with zippered storage) and an extra external pocket on each side (four in total). What’s more, the Mariposa’s foam backpanel is removable and doubles as a sit pad, which is a nice touch. One of the biggest distinctions is durability: The Gossamer Gear’s 210- and 100-denier Robic nylon is less durable than the Circuit’s 400 Robic, and our tester’s hipbelt wore through during his thru-hike of the CDT. The Circuit also has more sizing options. For $15 less, we give the edge to the Circuit, but the Mariposa is nevertheless a wildly popular UL pack, for good reason. For more, read our review of the Gossamer Gear Mariposa.
The Circuit is one of the best ultralight and thru-hiking packs, period. It's available in a wide range of sizes and offers impressive load carrying for its weight. While it lacks the Dyneema construction found in many other ultralight packs, the Robic nylon is impressively hardwearing.
Comfort
Organization
Weight
Durability
Water Resistance
Sustainability
Splitting the difference between minimalist UL models and fully featured haulers, the Exos (women's Eja) is one of the best options for those curious about lightening their load. However, it’s not as durable or lightweight as many true-blue ultralight packs.
Comfort
Organization
Weight
Durability
Water Resistance
Sustainability
This ultralight pack is right up there with the category’s elite in terms of carrying capacity and organization, and it features better padding than most. The Mariposa isn’t super durable, though, and we had a sample issue with its hipbelt during our CDT thru-hike.
Comfort
Organization
Weight
Durability
Water Resistance
Sustainability
The ULA Equipment Circuit is a far cry from the frameless, floppy UL pack. After wearing this pack and experiencing its applause-worthy comfort-to-weight ratio firsthand (the Circuit feels frankly luxurious for an ultralight pack), we count ourselves big fans. If you don’t want to spend up for a Dyneema design, it’s one of our favorite alternatives; along with the cost savings, you get significantly more padding and a wide range of fit options. And while the Circuit’s Robic nylon isn’t waterproof, it’s nevertheless impressively durable. All told, ULA’s iconic backpacking pack is a great tool that will get you through multiple seasons and thru-hikes in comfort and style—and you won’t be the only one carrying it on the trail.
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