Hyperlite Mountain Gear Southwest 40 Backpack Review
The smaller sibling in Hyperlite Mountain Gear’s cult-favorite lineup, the Southwest 40 ($395) is a premium ultralight backpack built almost entirely from Dyneema. Long-term durability and inherent waterproofing are major highlights, paired with excellent build quality and a minimalist yet effective organizational layout. While the Southwest’s limited adjustability and sparse padding mean it won’t appeal to comfort-first backpackers, it’s an exceptionally dependable option that has proven itself on the backs of countless thru-hikers. We like the 40-liter version best for short overnights and experienced minimalist packers.
Comfort
Organization
Weight
Durability
Water Resistance
Sustainability
Weight
1 lb. 13.7 oz.
Stated Load Limit
40 lb.
Fabric(s)
200D Dyneema Woven Composite
Adjustable Torso
No
# of Pockets
5
Access
Top
Capacities
40, 55, 70L
Included rain cover
No
Pros
Cons
Hyperlite Mountain Gear Southwest 40
Editor’s note: In 2025, Hyperlite updated its entire Southwest lineup. Available in 40-, 55-, and 70-liter versions, the new Southwest uses a Dyneema Woven Composite fabric, which is more durable than the DCF of the outgoing version without any weight penalty. Hyperlite also redesigned the backpanel and shoulder straps for a closer, more secure fit, and revamped the side pockets to make items easier to access.
The Hyperlite Mountain Gear Southwest 40 is a stripped-down ultralight pack, and that comes with inherent comfort tradeoffs. Its design intentionally forgoes generous padding, complex suspension, and extensive fit adjustments—especially when compared to more traditional backpacking packs like the Osprey Atmos AG or Gregory Baltoro. This minimalist approach won’t work for everyone, and its limitations become more noticeable as pack weight increases.
That said, as long as I kept my load under about 40 pounds, I was pleasantly surprised by how well the Southwest distributed weight. Two vertical aluminum stays and a thin foam back panel provide enough structure, and the medium-density cushioning in the shoulder straps and hipbelt felt sufficient. I never found myself wishing for more padding or rigidity. Unlike bulkier backpacking packs, the Southwest’s low-profile design hugs close to the body—in my opinion, this stability leads to comfort.
I did notice the lack of load lifters on the Southwest. They aren’t necessary for minimal overnight loads, but with heavier carries, I’d miss the ability to fine-tune how the weight sits on my shoulders and back. Breathability is also limited since the pack rides directly against your back rather than using a suspended mesh panel. I did get a bit sweaty while ascending to a sub-alpine campsite in cool 40°F temperatures, but that’s typical for me regardless of the pack.
The Hyperlite Mountain Gear Southwest 40 sticks to a simple, minimalist organization scheme that will feel familiar to experienced ultralight backpackers. The pack features one large main compartment with a roll-top closure, two external side pockets that easily fit a Nalgene or a small backpacking tent, a large external rear pocket, and two generously sized hipbelt pockets. The main compartment is featureless, aside from a small hanger for a hydration bladder.
Those coming over from a more traditional backpacking backpack might find the Southwest too sparse, but I found it fully sufficient with the addition of a few of my own stuff sacks and packing cubes. I put larger items like my sleeping bag, pad, stove, food, and extra layers into the main compartment, then used one side pocket for a water bottle and the other for my tent. Smaller items—headlamp, lighter, toiletries, and odds and ends—went into stuff sacks, which kept them from disappearing into the open interior. It’s worth noting that Hyperlite also offers a few organizational add-ons should you want them, including an Inside Pack Pocket, Bottle Pocket, and Shoulder Pocket.
The Southwest’s external access is ideal for grabbing and stowing items while on the go. The large rear pocket is perfect for quickly stashing a puffy, rain jacket, or camp shoes. The hipbelt pockets are a standout feature—among the largest I’ve used—easily swallowing a phone, snacks, and other essentials you want within reach while hiking. And all of the external pockets are made from durable Dyneema fabric, which sets the Southwest apart from other Hyperlite models that rely more heavily on mesh. Overall, the organization is functional but intentionally sparse, rewarding users who value simplicity over built-in compartmentalization.
At 1 pound 13.7 ounces, the Hyperlite Mountain Gear Southwest 40 is impressively light—especially when compared to more traditional backpacking packs. The Southwest achieves this by embracing a minimalist design. You give up features like thick padding, suspended backpanels, and myriad zippered pockets, but in exchange, you get a pack that feels exceptionally nimble and easy to carry. In my experience, the tradeoff is well worth it—the pack’s low weight contributes directly to how comfortable and stable it feels when moving over long distances.
The Southwest is only bested in weight by a few select ultralight packs, but none can match its combination of weight and durability. The Zpacks Arc Haul Ultra 40L, for example, weighs just 1 pound 5.2 ounces, but relies on mesh pockets and a much thinner body fabric. The ULA Circuit, which has a 40-liter main compartment and 68 liters of total storage when accounting for external pockets, weighs 2 pounds 6.5 ounces, but uses a less durable nylon. More traditional designs tip the scales even higher: the Osprey Exos 38 comes in at 2 pounds 11.1 ounces, while the Osprey Atmos AG 50 weighs a hefty 4 pounds 5.1 ounces. Against this backdrop, the Southwest 40 strikes an excellent balance between low weight, durability, and real-world functionality.
The Hyperlite Southwest 40 is built to take abuse, thanks in large part to its Dyneema construction. Known for its exceptional strength-to-weight ratio, Dyneema is one of the most sought-after materials in ultralight gear. Updated in 2025, the pack body now uses a fully woven 200-denier Dyneema fabric, which is tougher and more abrasion-resistant than previous iterations while maintaining the same impressively low weight.
In use, the Southwest has proven itself highly resistant to scrapes and abrasion. It’s a pack I can toss on the ground, sit on, and drag through brushy forests without hesitation, which helps explain why it’s long been trusted by thru-hikers on extended, months-long outings. Dyneema will form holes over time, but the holes don’t spread like they do in other fabrics, and are easy to patch or glue shut.
The Southwest’s hardware also inspires confidence—while all the buckles are plastic, they feel sturdy rather than cheap, and the waterproof zippers on the hipbelt pockets operated smoothly throughout testing. While it’s undeniably expensive for a pack in this capacity range, the investment makes sense for anyone chasing the holy grail of lightweight durability. I have always loved seeing other battered, dirty, and well-loved Hyperlite packs out in the wild, and am excited to see how mine withstands adventures over time.
Water resistance is one of the Southwest 40’s standout strengths. Dyneema composite fabrics are inherently waterproof, and with a Dyneema body paired with a roll-top closure and watertight zippers, this pack is exceptionally well sealed against the moisture you’re likely to encounter on trail—as long as there are no holes in the fabric. In practice, that means far less worrying about rain, wet brush, or setting the pack down on damp ground.
I tested the Southwest on a cool fall hike through a wet forest en route to an alpine lake, and it repelled water impressively well. Brushing against soaked vegetation and hiking through consistently damp conditions never allowed moisture to make its way into the pack. While I haven’t yet used the Southwest in a full downpour, based on this performance, I’d trust it over most backpacking backpacks in wet conditions. It’s a genuine luxury to not need a pack cover, dry bags, or plastic liners to keep gear dry.
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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: 5’9”; 19-inch torso
Size tested: Medium
The Hyperlite Mountain Gear Southwest 40 comes in five torso sizes, which helps dial in fit despite its minimalist suspension. I’m 5’9” with a 19-inch torso, and I tested the pack in a size Medium (17–19 inches), which fit me well and felt appropriately balanced on the trail.
Once you choose from Hyperlite’s five sizes, there’s little more you can do to alter the fit of the Southwest. There is no torso-length adjustment, and the hipbelt is fixed in size. For my purposes, this wasn’t a concern, but if you’re purchasing the pack to share or want it to accommodate a changing body, take note that it's not the most customizable pack.
One minor drawback is the sternum strap adjustment. Instead of sliding up and down on the shoulder straps like many mainstream packs, the sternum strap must be fully detached and reattached to change its vertical position. That makes it more cumbersome to adjust on the fly and slightly more involved overall. Another drawback is the lack of load lifter straps. I haven’t found this to be an issue with loads under 30 pounds or so, but it’s worth noting if you’re accustomed to using load lifters to fine-tune fit.
Gossamer Gear Mariposa 60 ($315): A Different Minimalist Approach
While the Gossamer Gear Mariposa 60 and the Southwest are both aimed at the same demographic—backpackers who go fast, far, and light—these two packs have different selling points. The Mariposa makes more concessions to user-friendliness, with a lid (which features a small pocket), load lifters, and a removable, padded backpanel that doubles as a sit pad. What’s more, its shoulder straps and hipbelt have a bit more cushion than the Southwest’s, and you can swap out the hipbelt to nail your perfect fit. However, the Mariposa’s fabric—100D Robic nylon, with 210D on the bottom—is much less durable than the Southwest’s Dyneema, and isn’t waterproof. You’ll have to baby the Mariposa more, and it’s a couple of ounces heavier and rated to 35 pounds (compared to the Southwest’s 40). All told, the Mariposa is more comfortable, but the Southwest is a longer-lasting design for burlier hikes and heavier loads. For more, read our review of the Gossamer Gear Mariposa.
ULA Equipment Circuit ($300): A More Refined Fit
Along with the Southwest, the 68-liter ULA Equipment Circuit is one of our favorite load-eating ultralight packs. We’ve comfortably schlepped 35 pounds with it thanks to a suspension consisting of a hard foam framesheet, carbon-fiber-and-hard-plastic hoop, and an aluminum stay. The Circuit has an almost identical pocket layout (roll-top, large side pockets, front shove-it pocket, hipbelt pockets) and a similarly impressive weight-to-capacity ratio—it’s a tad heavier than the Southwest but offers significantly more capacity. What stands out on the Circuit is ULA’s commitment to providing a wide range of sizing options: you can choose from unisex torso sizes ranging from small to XL, hipbelt sizes XS to XXL, and two shoulder strap designs. Even though the Circuit’s 400-denier nylon fabric isn’t as tough as the Southwest’s and it’s not waterproof, a PU coating keeps a decent amount of moisture out and makes the pack durable enough to last many seasons. For more, read our review of the ULA Equipment Circuit.
The smallest sibling in Hyperlite’s cult-favorite backpack line, the Southwest 40 is headlined by its Dyneema fabric, which provides excellent durability and inherent waterproofing. The 40-liter version is best for short overnights and experienced minimalist packers. Drawbacks include a lack of adjustability, poor breathability, and sparse padding.
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 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
Is the Southwest 40 for You?
If you’re into ultralight backpacking—or at least ultralight curious—the Hyperlite Mountain Gear Southwest 40 should be high on your list. This lineup sets the standard for ultralight performance, combining durable, waterproof Dyneema construction with excellent build quality and a thoughtfully minimalist design. It’s a significant investment, but the payoff is a pack that feels built to last—and could easily be the last backpacking pack you ever buy.
The 40-liter Southwest is best suited for gear-heavy day hikes, short overnight trips, or truly minimalist backpackers who keep their kits dialed. For longer outings or trips that require carrying multiple days’ worth of food, we recommend stepping up to the 55-liter version, which offers more breathing room without sacrificing the Southwest’s core strengths.
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