One of the few downsides in the industry-wide transition to internal-frame packs is ventilation. Enter the Atmos line from Osprey, and most recently, the Atmos AG pack. This bag has been designed from the ground up to keep your back dry without sacrificing the other things that we all love about the internal-frame design. After a full season of backpacking trips, including multiday treks in hot weather in Utah, we’ve come to the conclusion that this is the best ventilating internal-frame pack on the market. Below are our thoughts on the Atmos AG's ventilation, organization, weight, fit and comfort, and more. To see how the Atmos stacks up as an all-around design, check out our comparison table and article on the best backpacking packs.


Unmatched Ventilation, Typical Osprey Quality

The big news here is along the back—one large suspended mesh panel covers the entire backpanel and hipbelt of the Osprey Atmos AG. Dubbed Anti-Gravity (hence the AG in the name), even the shoulder straps have the same open webbing. The results are impressive: never before have we gotten to camp, removed the pack and not had to peel some part of our sweaty shirt away from our skin. It just works, and expanding the concept to the hipbelt is seamless. If your number one consideration in buying a backpacking pack is ventilation, you can stop reading—the Osprey Atmos AG is the one.
Osprey Atmos AG (back panel)

Most of us look for a little more, however, and what takes the ventilating design from merely good to great is the fact that it doesn’t compromise the rest of the backpack. The Atmos AG is simply another quality Osprey item: it can haul a multi-day load in comfort, has thoughtful organization, and is made with durable materials that haven’t shown any signs of excessive wear over the past year. The curved backpanel, which creates the open space for air to reach your back, does cut into the main compartment a little, but it’s still easy to fit large items like a standard bear canister inside.


If organization is a priority, the Atmos AG has a pocket, lash point or gear loop for just about any item you can think of. To start, you get the standard array of 2 zippered pockets in the top lid, 2 mesh water bottle holders, a sleeve for a water reservoir, and a very large mesh stuff-it pocket along the front of the pack.

The features we’ve found most convenient are the zippered pockets that flank the mesh stuff-it pocket—they’re quite large and can swallow bulky items like a water filter or extra fuel canisters—and the 2 hipbelt pockets. These too are on the big side and should easily accommodate a modern smartphone in a case (we were even able to fit a point-and-shoot camera in its case).
Osprey Atmos backpack storage

One area for improvement would be a zippered access into the main compartment. The Atmos has a standard top loader design, which makes it a pain to dig through and find an item that’s hidden deep inside, although the zippered sleeping bag compartment at the bottom helps some. Adding another zipper would tack on some ounces to the total weight, but we’ve come to appreciate the quick and easy access to the main compartment you get with this feature.


At 4 pounds 9 ounces in a medium frame, the Atmos AG is competitively lightweight for what we consider a luxury pack. Construction and features vary widely even among backpacks of a similar capacity: on one of the spectrum are the ultralights (around 2-3 pounds) that only have a couple pockets and are made with very thin materials; and at the other are traditionalist packs with premium features and durable fabrics at the cost of weights that creep towards 5 pounds. The Atmos AG falls towards the premium side, although at 4 pounds 9 ounces, it’s not excessive (the very popular Osprey Aether 70 AG weighs 5 lbs. 3 oz.). In the end, considering how well it can carry a load reaching 50 pounds, we consider the empty weight completely reasonable.

Fit and Comfort

When I slid on the pack for the first time, I was struck with how well the Atmos fit. The mesh backpanel and hipbelt naturally want to fold inwards, which means the pack practically hugs you. It makes a strong first impression, and we’ve found it to be very comfortable even after logging serious miles on a number of overnight and extended trips. Even though the sculpted backpanel does pull the load a little bit away from you, we never felt any disconnect or the sensation of the weight pulling us backwards.  
Osprey Atmos AG (load lifter straps)

To be clear, the Atmos AG is not our absolute favorite pack for carrying a heavy load (45 plus pounds)—that honor is reserved for the Gregory Baltoro. That being said, the Atmos holds its own for multiday trekking, and even on trips where we’ve brought along extra items for gear testing, it’s been decently comfortable. This is all despite using a suspended mesh hipbelt design rather than thick foam—a testament to the Anti-Gravity technology.

What We Like

  • A thoughtfully designed and really well implemented ventilation design. It’s the best such high capacity pack we’ve ever tried.
  • Solid carrying comfort, despite not relying on foam padding for support.
  • Good organization overall, with large pockets to divvy up items.

What We Don’t

  • A zippered access to the main compartment would make it easy to grab items that aren’t at the top or in the bottom sleeping bag compartment.
  • The pack has developed a noise around the hipbelt that is pretty noticeable when on the go—it resembles a low-pitched groan.

Osprey Atmos ventilation

Comparison Table

Pack Price Weight Fabric Pockets Access Capacities
Osprey Atmos 65 AG $270 4 lb. 9 oz. Nylon (100D x 630D) 8 exterior Top 50, 65L
Gregory Baltoro 65 $299 5 lb. 1 oz. Nylon (210D & 300D) 8 exterior Top, front 65, 75, 85L
REI Traverse 70 $239 4 lb. 13 oz. Nylon (210D & 630D) 9 exterior Top, front 70L
Osprey Aether AG 70 $310 5 lb. 3 oz. Nylon (210D & 500D) 7 exterior Top, front 60, 70, 85L
The North Face Banchee 65 $239 3 lb. 9 oz. Nylon (210D)  8 exterior Top 35, 50, 65L

The Competition

As a high-capacity ventilation pack, the Atmos AG stands alone as our top pick. But you do pay a slight premium for the Anti-Gravity suspension, and there are a number of other excellent backpacking models to consider. REI’s Traverse 70 has long been a favorite of ours, and their updated model uses a creative compression system for keeping the load close to your back (see our in-depth review here). It’s cheaper ($239) than the $270 Atmos, but the firm padding is a little less comfortable unless you really load it with weight. The other part of the decision may come down to how highly you prioritize back ventilation—the Traverse falls short of the Atmos in that respect.
Osprey Atmos AG (Shuksan)

For carrying a very heavy load, the Gregory Baltoro 65 as well as the Osprey Aether AG 70 are slightly better options, and both offer a zippered access to the main compartment (a notable omission with the Atmos AG). We love all 3 of these packs—it shouldn’t come as surprise that they’re near the top of our list of best backpacking packs—and it’s hard to separate them. To keep it simple, we would break them down as follows: for comfort above all else, get the Baltoro (for more information, check out our review); the Aether is for backpackers carrying a lot of weight or light mountaineering (reviewed here); and the Atmos gets the nod for weekend backpackers, thru-hikers, or those that backpack a lot in the heat.

All in all, the Osprey Atmos AG is an excellent step forward for internal-frame packs, effectively addressing a common complaint for backpackers. For that reason alone, it deserves a lot of praise. Thankfully, it’s not a one-trick pony, and we think this pack’s popularity within the core backpacking market will push the competition to respond with more ventilating options. Sweaty backs, rejoice!


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