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Hyperlite Mountain Gear Unbound 40 Backpack Review

Made with thru-hikers in mind, the Hyperlite Mountain Gear Unbound 40 backpack is everything you need and nothing you don’t. This pack is essentially waterproof, incredibly durable for the weight, and has convenient pockets galore. We put our Unbound pack to the test over hundreds of miles in the Sonoran Desert, and we think it’s a big win for long-distance hiking and ultralight backpacking.

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Quick Specs

Hyperlite Mountain Gear Unbound 40

Price: $369

Weight: 1 lb. 13.6 oz.

Volume: 40 L

Max Weight Rec.: 35 lb.


  • Ultralight
  • Practically waterproof
  • Very durable for the weight
  • Spacious hipbelt pockets
  • Spacious front pocket
  • Convenient bottom pocket
  • Can remove some components to save weight


  • Expensive
  • Not as padded
  • Torso isn't adjustable



Weighing in at just under two pounds, this pack is very light. Compared to our other favorite packs from our Best Backpacking Backpacks list, the HMG Unbound 40 is in the top three lightest backpacks. It’s beaten out only by the less durable Zpacks Arc Blast and the not as water-resistant Gossamer Gear Gorilla.

Keeping weight to a minimum is important for reducing stress on your body. We like to travel light so we can go further, go faster, and generally be more efficient on trail. Worrying less about the weight on your back usually means enjoying your hike more.

About as close to waterproof as backpacks get

The Unbound is made with Dyneema fabric, which is waterproof. The seams are also taped for even more water-resistance. So why don’t we just call this backpack waterproof? Well, 100% waterproof bags are heavy and made with a rubberized material that’s not practical for backpacking. In practice, it’s VERY tough to make a truly waterproof backpack – think submerging it in a lake – but the Unbound 40 is about as close as it gets for normal backpacks.

This is one of our favorite features of the Unbound 40 because it allows us to hike through rain without worrying about important items – like our sleeping bag and extra clothing – getting drenched. Pairing this backpack with waterproof stuff sacks will give you double protection and peace of mind when the weather is nasty.

Bottom pocket

Following in the very successful footsteps of cottage brands, like Pa’lante Packs and Atom Packs, Hyperlite added a bottom pocket to the Unbound 40. This is a fairly new feature on mainstream backpacks, but we think it’s great, and we expect more companies to start incorporating them.

The bottom pocket has quickly become my favorite feature on ultralight backpacks – to the point where it feels strange for me to use one without this storage option. This pocket can be used to store things like snacks, drink mixes, or gloves for easy access on the go. I’ve even used it to change out of my rain jacket after a downpour without having to stop hiking – very handy on the Colorado Trail where the weather changes constantly.

Innovative front pocket

The front pocket is pretty unique as it has two access points – a standard top entry and then a little shelf pocket at the bottom that can be accessed independently. We use the shelf pocket to hold smaller items we don’t want to have to search too hard for when we need them – like sunscreen and tent stakes.

The fabric is Dyneema stretch mesh – a departure from the Hardline with Dyneema front pocket of the Southwest line and the Dyneema net front pocket of the Windrider series of packs. We have a slight preference for the stretch mesh of the Unbound because it looks more sleek, keeps items more secure, and cuts down on front pocket bulk that can make your load feel unbalanced.


Excellent pockets

The bottom pocket and front pocket of the Unbound 40 are so good that we had to give them their own shoutout, but we really love all of the pockets on this pack.

The side pockets sit low, so it’s easy to pull out water bottles while on the move. The hipbelt pockets are large and constructed with waterproof zippers, so you can keep small items and electronics secure.

The roll-top main opening is large and convenient for getting things in and out of the pack body. Hyperlite also ditched the velcro that they use on the opening of their other packs – this is awesome because that velcro had a tendency to catch on clothing.


Durable, especially for the weight

We’ve been using Hyperlite Mountain Gear backpacks for over a decade. We’ve put these packs through everything – from dragging them through granite scrambles to hundreds of miles through the prickly Sonoran Desert – and we can attest to their exceptional quality of construction.

The Unbound 40 is made from the same DCH 50 (main body) / DCH 150 (bottom) – Dyneema composite fabric hybrid – that the industry-leading HMG Southwest 2400 and Windrider 2400 are constructed with. This fabric has an unrivaled weight-to-strength ratio, so this backpack is a worthwhile investment that will last you for thousands of miles if treated with a little care.


Good capacity for a variety of trips

We find that the 49L total capacity (40 internal, 9 external) is perfect for nearly any trip with ultralight gear. It’s big enough that you can pack along a bear canister or a more spacious backpacking tent if you want to, but not so big that you’ll have a hard time filling it.

If you find that you need a little extra space, you can bump up to the Unbound 55 which has an internal capacity of 55L and an external capacity of 9L.

For those who need help deciding between the two – we recommend the Unbound 40 to anyone with a fairly dialed in ultralight setup (base weight around 10 or so lbs.) and the Unbound 55 for hikers who like carrying some extra/bulky luxury items or want the option to use their pack in winter.


Comfortable when packed efficiently

The Unbound 40 is quite comfortable to wear for long periods if you have your gear dialed in to 30 lbs. or less. Hyperlite lists the max carry as 40 lbs, but we think the comfort range sits closer to 35 lbs.

The shoulder straps and hipbelt are padded, but it’s minimal. So taking extra care to pack your backpack efficiently is key.



Some components of the Unbound 40 can be removed, so it easily transitions from a full-featured thru-hiking pack to a trimmed down weekend hauler. Removable components include the hipbelt, aluminum frame stay, and compression straps. That said, we don’t recommend removing these items unless your total carry weight will be around 20 lbs.



(Honestly, we absolutely love this pack & found very few things to put here)


Compared to other packs on our Best Backpacks list, the Unbound is among the most expensive. But when you consider what you’re getting – exceptional durability, ridiculously low weight, and virtual waterproofness – we say the Unbound 40 is well worth the cost for hikers looking to go light without making sacrifices on longevity or convenience.

Minimal padding

The Unbound 40 isn’t going to be as supportive as a heavily padded traditional pack with a suspension system, but it does include some cushion on the hipbelt and shoulder straps. We find this backpack to be most comfortable with a total packed weight of 30 lbs. or less, which can be a bit tough to achieve if your gear isn’t dialed in.

Bottom Line

The Hyperlite Mountain Gear Unbound 40 is really giving our longtime favorite, the HMG Southwest 2400 a run for its money. This innovative pack should be at the top of the list for long-distance hikers due to its efficient design, weather protection, and low weight. While it’s a bit expensive, the Unbound 40 is a worthwhile investment for hikers looking for a backpack with an unrivaled balance of durability and weight.