“If your gear closet has a 50 litre hole in it, the Atmos will be a welcome addition” Rating 9/10

Hailing from a small town in Southwest Colorado, Osprey have been making hardy packs for thru-hiking, mountain biking, mountaineering and pretty much everything else since 1974.

Occupying the mid-capacity spot in Ospreys thru-hiking range, the Atmos comes in 50L and 65L options, as well as the women’s specific Aura — also available in 50L and 65L.

I’ve been putting the 50L Atmos through its paces, and with a laundry list of features and comfort technology built in, this pack has quite a lot to offer. Lets dive in.

osprey atmos 50l bag

Backpack from space

The most notable aspect of the Atmos is the Anti-Gravity (AG) suspension system, which is a suspended panel of non-stretch mesh with 7mm holes that covers the entire back of the bag, as well as the waist straps.

I was pretty skeptical of the AG system when the Atmos bag arrived, and it wasn’t until I pulled the pack on that I realized what Osprey has achieved here.

The 50-litre Atmos is designed to support about 18kg/40lbs, and despite the pack being suspended away from your body, it’s surprisingly stable and supportive. Once you exceed this weight, the AG suspension system begins to flex a bit, making the pack feel squishy.

With the bag loaded, the AG mesh conforms to your body, and feels a bit like a firm hug. Game changing isn’t a term to be used lightly and one I don’t like to use often, but the Atmos has well and truly earned this accolade. Most backpacks offer something called forced comfort, meaning your body needs to conform around the structures of the bag. With the Atmos it’s the opposite, 90-percent contact area is the suspended mesh and the pack literally forms to you.

To date this is the most comfortable pack I have worn, however by our scales the AG system adds a bit of weight, coming it at 2.21kg / 4.87lbs. When you look at other 50L packs like the Deuter ACT Lite 50 + 10 (1.73kg / 3.81lbs), Lowe Alpine Zephyr (1.85kg / 4.08lbs), Berghaus Trailhead 50L (1.5kg / 3.31lbs) and Mountain Hardwear Ozonic 50 OutDry (1.73kg / 3.81) the Atmos is definitely on the weighty end of the spectrum.
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The Atmos is available in three sizes, and our size medium pack is true to the size chart and was exactly 50L in volume — the sizes vary in volume in three litre increments.

Even within the three sizes there’s a fair bit of adjustability built into the pack. The harness offers four inches of vertical range and the waist strap has six inches of adjustability. The shoulder straps are independently adjustable, something I’m not a fan of as they may end up uneven if you’re in a hurry. It’s also not immediately clear how to adjust the straps as the mechanism is hidden behind the harness. That said, as long as you’re not lending the pack out, you should only have to adjust it once, and Osprey does offer printed guide markings to make sure you’ve got it right.

Moving the waist strap is a simple velcro adjustment, but being a slim build I left the waist strap in it’s smallest position.

osprey atmos 50l bag

osprey atmos 50l bag osprey atmos 50l bag

Straps straps and more straps

Inside the pack it’s pretty minimalist, which is a good thing as everybody packs differently. There’s a false bottom controlled by two pieces of webbing that allow the pack to either be one continuous space, or divide the bottom into a dedicated sleeping bag pocket of you want to ditch the stuff sack. The pack also sees a hydration bladder sleeve too.

Like most packs in its category the Atmos is a top-loading access bag, meaning it needs to be packed from the bottom up. There’s no side access zippers so make sure you keep your rain jacket close to the top.

The Atmos also comes with a removable floating top lid which allows a bit of easily accessible storage, though when in use the standard pack lid is very much in the way, and I never really found a good spot for it.

On the outside there’s gear loops for ice axes and trekking poles, compression straps, and even an external stretch pocket perfect for flip flops, frisbee’s and other annoyingly shaped items. I also loved the dual entry water bottle pockets which allows a bottle to be stored vertically or at an angle making it easier to reach with the pack on. There’s also wonderfully oversized ‘snack pockets’ on the waist belt.

A notable omission from the 50L Atmos are dedicated sleeping pad straps which do come on the larger 65L version. The compression straps on the side work, but it’s not a particularly clean solution.

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Final thoughts

The Atmos has just about every bell and whistle a backpack can have, and for a pack this size isn’t overly expensive at $329. With three torso sizes and considerable adjustability both on the harness and the waist strap the Atmos is sure to fit a wide variety of body types and shapes.

Considering it’s size the Osprey pack is ideal for your first hike-in-hike-out camping trip or a three day bush adventure — provided it’s a warm weather trip. If you’re planning to head out for longer or in the snow, and you’re not and experienced ultralight packer, it’s probably best to look at something a bit bigger.

The few niggles I do have with the bag are definitely not deal breakers, but the lack of sleeping pad straps is a bit of an oversight, especially considering they’re present on the 65L version.

It’s also not the lightest pack on the market by a long shot, but for the comfort on offer I’ll happily carry a few extra grams. That’s saying something considering I own a titanium spork because it’s lighter than the nylon version.

Overall if your gear closet has a 50L hole in it, the Atmos will be a welcome addition.

osprey atmos 50l bag
Osprey Atmos 50l review
Closing Remark
“If your gear closet has a 50 litre hole in it, the Atmos will be a welcome addition”
Ease of Use
AG suspension
Dual entry waterbottle pockets
False bottom allowing for sleeping bag pocket
Lack of sleeping pad straps
Floating lid and standard lid don't play nice together
Our Rating