Hyperlite Mountain Gear Southwest 40 Backpack Review

Dyneema is a hot ticket in ultralight gear, and for good reason: It's one of the strongest materials in the world relative to its weight, resists moisture very well, and is incredibly light. Maine-based Hyperlite Mountain Gear leads the charge in utilizing Dyneema, and we were eager to test their Southwest 40 (formerly the 2400 Southwest), a 40-liter pack made for rugged terrain. In the end, while we knew to anticipate the feathery weight and superb durability, we came away even more impressed by the pack's comfort and functionality. Below we outline our experiences with the Southwest. To see how it stacks up to the competition, see our articles on the best backpacking packs, women's backpacking packs, and ultralight backpacks.

Editor’s note: We tested the past-generation Southwest 40 for this review, which has since been updated. The two designs are largely similar, although the latest model is built with a Dyneema Composite Hybrid (DCH) construction that offers better abrasion resistance compared to standard Dyneema. We've outlined the changes where applicable in the text below.
 

Table of Contents

• Weight
• Carrying Comfort
• Organization and Pockets
• Build Quality and Durability
• Ventilation
• Fit and Sizing
• What We Like/What We Don't
• Comparison Table
• The Competition

Performance

Weight

The Hyperlite Mountain Gear Southwest 40's 1-pound-13.9-ounce weight (for the white version in a size medium) is noteworthy for a couple of reasons. First, it puts the 40-liter pack in a competitively small group of sub-2-pound backpacking designs. For comparison's sake, most competitors check in at least a few ounces heavier, including Osprey's Eja 38 (2 lb. 11 oz. for a size M/L) and Gregory's Facet 45 (2 lb. 9.6 oz. in a medium). Second—and even more impressive—is the remarkably few compromises the Southwest makes in order to maintain this low weight. Even loaded down for a multi-day trip, the pack kept my gear organized and was noticeably comfortable on my back.
 

We have Dyneema to thank for the Southwest's impressive combination of low weight and toughness. Formerly known as Cuben Fiber, Dyneema is among the strongest materials in the world in terms of strength-to-weight ratio. Although very much still a minimalist pack in terms of build and features (more on this in the "Organization and Pockets" section below), the Dyneema and Dyneema Composite Fabrics (DCF) throughout—on the main body, hipbelt, shoulder straps, and external pockets—shave considerable ounces compared to packs of the same capacity. After several long, heavy-mileage days in the Mount Baker backcountry, I was grateful for the Southwest’s sleek build. It’s no wonder Hyperlite’s packs have a cult-like following among thru-hikers. (Note: The latest version is made with Dyneema Composite Hybrid—DCH for short—which is even more abrasion-resistant than standard Dyneema and DCF). 
 

Carrying Comfort

As soon as I donned the Hyperlite Southwest 40, I was struck by its comfortable design and fit. Weight and interior space are understandably important considerations when looking at packs, but comfort is always paramount. The Southwest’s lightweight and pliable materials had me initially fearful, but my worries were expelled as soon as I stuffed my gear inside and threw the pack over my shoulders. The 1/4-inch foam backpanel pad added a nice, cushioned layer that kept the contents of the pack from poking into my back, and the removable aluminum stays were effective in distributing the weight (I haven’t attempted to wear the pack without them, although doing so would shave 4.4 oz.).
 

For a minimalist pack, the Southwest’s hipbelt is reasonably padded and snug. Even during long days on the trail with up to 30 pounds of weight (the pack’s maximum capacity is 40 lb.), I’ve experienced no hotspots or discomfort. That said, my experience with the shoulder and sternum straps has been less than ideal (this strikes me as a female-specific fit issue with a unisex pack—for more, see the "Fit and Sizing" section below). It took a few trips to break in the stiff shoulder straps, but they’ve become comfortable and feel adequately cushioned despite initially digging in underneath my armpit. The sternum straps, on the other hand, have been harder to tailor. In the end, I found that their optimal position on my upper half requires defacing the poorly placed Hyperlite logo—but all in the name of comfort, right? With this adjustment, the band sits perfectly across my chest.
 

Organization and Pockets

The Southwest’s design is undeniably basic, with only a single main compartment and three exterior pockets for organization (plus two hipbelt pockets). Similar to other models in Hyperlite's backpacking collection, the body of the Southwest is basically a tube that’s closed with a roll-top system, sealed at the top with a Velcro closure and fastened to the sides with buckles. This main compartment has a hydration bladder sleeve inside but is otherwise bereft of pockets and storage. I do wish Hyperlite had included an internal zippered pocket for personal items like a wallet or keys, as I found it hard to find a spot for these otherwise.
 

On the outside of the pack, the Southwest features three generously sized stuff pockets and two hipbelt pockets that add an additional 9.8 liters of capacity. I tended to use the three large stuff pockets for extra layers, food, water, or damp items that I wanted to keep away from the rest of my gear. Importantly, instead of standard mesh, all three pockets are made with Dyneema-based Hardline, which bodes well for durability but means that items stuffed here won’t dry as well or as quickly. That said, Hyperlite did include a hole at the bottom of all three pockets, allowing them to drain water.
 

As someone who snacks often, I’m a sucker for sizable hipbelt pockets, and the Southwest’s easily fit the bill. The two zippered pockets are water-treated for added insurance against the elements, and I especially love the generous size: One pocket easily swallowed my GPS device, smartphone, handwarmers, and snacks. In my mind, the small addition of hipbelt pockets transforms the Southwest from ultralight hauler into a more fully featured backpacking pack.
 

Build Quality and Durability 

Despite its lightweight focus and minimalist build, the Hyperlite Southwest 40 has shown no signs of wear throughout its extensive testing. Although I chose the 50-denier (D) white version (the black Southwest 40 model uses a thicker 150D fabric for $20 more), it has withstood being battered, dropped, and dragged, and so far has proven indestructible (the base of both models is 150D). I’ve had no seam issues, either—they’ve all held up tight with no signs of fraying, and the seam seal has not peeled or worn at all. Do keep in mind, however, that regardless of how strong Dyneema may be, the spaces between the woven fibers are vulnerable to puncture. Importantly, Hyperlite did aim to address this issue with the latest pack by using a polyester face fabric for added abrasion resistance—while retaining all the benefits of Dyneema. The Southwest will still require more attentive care over time than burlier models, but overall durability is quite impressive, especially for a UL design.
 

What takes Dyneema packs from good to great is the fact that they don't compromise waterproofing. On one particularly frigid day of hiking in the Whistler alpine, we were pelted with rain and sleet in near-freezing conditions. Towards the end of the afternoon, I leaned the Southwest against a tarp leg for hours before realizing runoff from the roof was pouring directly onto the pack. After a brief moment of panic, I tore open the Velcro top to find my expensive camera gear completely dry. The Dyneema and roll-top closure had done an exemplary job of keeping out every droplet of moisture.
 

Ventilation

Hyperlite Mountain Gear is all about minimalism with very few bells and whistles, so you won't find any back ventilation systems on their packs. For those who run hot, this lack of airflow might be an issue. The pack's Dyneema (and now DCH) sits snuggly against the back and does not wick or breathe well, which has left me uncomfortably damp on a few occasions. Other lightweight packs, specifically those in Osprey’s lineup, use suspended mesh panels along the back, along with mesh-padded shoulder straps and hipbelts to promote airflow. That said, what you lose in ventilation with the Southwest you gain in interior space—the lack of added materials along the backpanel make this pack feel very spacious. 
 

Fit and Sizing

The Hyperlite Southwest 40 is offered in five different sizes (extra small, small, medium, large, and tall), and I opted for the medium based on torso length. While the shoulder straps were initially a bit wide for me, they became noticeably snugger once they softened. However, I find that women’s-specific packs from companies like Osprey are slightly better options for women with longer torsos (but not necessarily wider shoulders). But overall, the Southwest ended up being extremely comfortable after some breaking in, and the sizing was spot-on.
 

Other Versions of the Hyperlite Southwest

We tested the 40-liter Southwest for this review, and it also comes in 55-liter ($379) and 70-liter ($425) versions. As mentioned above, color also matters: The white version of the 40- and 55-liter packs are made with a 50D body fabric, while the black versions use 150D for $20 more (adding 2.9 oz. for the 55 and 2.5 oz. for the 40). The Southwest 70 uses 150D for both the white and black models, which cost the same as a result. Other than size and the optional beefier material, all capacities share an identical construction, organizational layout, feature set, and overall design.

Hyperlite also offers two largely identical packs in their Windrider and Junction, with the only discernible difference being the composition of the front and side pockets. The Windrider uses mesh for all three, which drain much quicker than the Southwest's Hardlline with Dyneema pockets—great for stashing wet layers and gear. The Junction marries the Southwest and Windrider designs with solid side pockets and a mesh front pocket. The Southwest is the only pack available in size extra small, and the Junction is negligibly heavier than the other two, but we appreciate the Hyperlite gives users options when it comes to storage.
 

What We Like

• Exceptionally light at under 2 pounds (for the white version) without skimping on comfort. 
• Main compartment is totally waterproof, even when faced with flood-like conditions.
• Despite its feathery feel and thin materials, the pack proved very durable throughout rigorous testing.
• We appreciate that Hyperlite offers the pack in five sizes, plus the choice between 50D or 150D fabrics.

What We Don’t

• Specialized Dyneema packs don't come cheap, and the Southwest is no exception at $349 for the 40-liter model ($369 if you opt for the 150D black version).
• Dyneema doesn’t breathe well, and there’s no back mesh panel to promote airflow. 
• Lack of internal pockets makes staying organized difficult.
• Our female tester had some comfort-related issues with the shoulder straps and sternum strap, although the former have broken in nicely over time.
   

Comparison Table

The Competition

While the Southwest 40's low weight and convenient features make it tough to compete with in the ultralight pack market, it’s not the only standout from Hyperlite. A relatively recent addition to their collection, the Unbound 40 is purpose-built for thru-hikers and long-distance backpackers who prioritize on-the-go access. While very similar in a lot of ways, organization is one key differentiator between the two: In place of the Southwest’s tall, angled side pockets, the Unbound has shorter pockets with wider openings that allow for easier access to water bottles and gear. You also get bungee straps above to affix longer items (like tent poles), a bottom compartment for stashing wet or dirty items, and dual mesh pockets (one large and one small) at the front. However, in testing the larger Unbound 55, we had trouble dialing in fit and found some of the components to be noticeably delicate. Unless the more generous storage layout is a selling point for you, we think the longstanding Southwest is the better Hyperlite design for $20 less.

Moving away from Hyperlite’s lineup, Zpacks is another UL specialist that caters to ounce-counters and minimalists. Their competitor to the Southwest 40 is the Arc Haul 40L, which uses a similarly tear-resistant and weather-ready Ultra 100 fabric in place of the Southwest’s DCH build. As its name suggests, the Arc Haul also boasts Zpacks’ unique “Arc” tensioning system that pulls the middle of the bag away from your back, allowing for noticeably better airflow. Other advantages include load-lifter straps for dialing in a closer fit, an adjustable torso height, and an all-in weight of just 1 pound 4.5 ounces (with a medium hipbelt and torso). All that said, the Zpacks will cost you an additional $50, uses thinner fabrics on the bottom (100D vs. 150D), and is relatively bereft of storage. You can purchase several pockets separately, but they will add to overall cost and weight. In the end, the Southwest strikes us as the less compromised UL design and the better value for what you get.
 

Gossamer Gear’s G4-20 gives the Southwest a run for its money in a few key areas at a significantly lower price point. Gossamer Gear accomplishes this with a Robic nylon construction (70D and 100D), which is quite abrasion-resistant but lacks the inherent waterproofing abilities and unbeatable strength-to-weight ratio of the Hyperlite's DCH fabrics. The G4-20 does manage to undercut the Southwest in weight by around 5 ounces (while offering an additional 2 liters of capacity), although the lack of internal frame is limiting for heavy loads (the pack is rated to 30 lb. compared to 40 lb. for the Hyperlite). In the end, a final decision will come down to your priorities and budget: For those willing to pay the premium, the Southwest is an excellent all-around performer for its weight; if you don't mind sacrificing protection and are willing to keep things light, the G4-20 is a well-built pack with a few advantages over the Hyperlite.

Last but not least is a more mainstream—but still competitive—UL pack to consider: Osprey’s Eja 38 (the women's counterpart to the Exos 38). At 2 pounds 11 ounces for a size M/L, the Eja 38 is a considerable 13.1 ounces heavier than the Hyperlite but offers impressive carrying comfort, ventilation, and organizational features for $129 less. Namely, you get a removable floating lid with two zippered pockets, ample exterior straps and attachment points, smartphone-friendly hipbelt pockets, and a suspended mesh backpanel that does a great job promoting airflow—far better than the Hyperlite's DCH fabrics. In the end, dedicated ULers will almost certainly want to stick with the lighter and more streamlined Southwest, but the Eja is a well-balanced option for those just dipping their toes into the ultralight space (it feels a lot more like a traditional pack than the Hyperlite).