The Osprey Packs Atmos AG 50 might just be the most comfortable backpack you’ll ever wear. Featuring the new Anti-Gravity ventilated suspension system, this backpack wraps around your upper torso, positioning itself properly on your hips for maximum load transfer and comfort. It’s even adjustable, so you can dial in the torso length and hip belt for a custom fit. The first time I put on the Atmos AG 50, I turned to my wife and said, “this might be the most comfortable backpack ever made.”
Backpack Suspension and Frame
AG stands for anti-gravity, an apt moniker for the new suspension system in Osprey Packs Atmos AG 50 backpack which is so effective at transferring loads to the big muscles of your hips that it feels like you backpack is lighter weight than it actually is. It’s pretty incredible actually. The pack feels great when it’s loaded up with 30 pounds of gear and water, enough to make you question whether a four pound pack with the Anti-Gravity suspension is more comfortable to carry than a 1.5 pound ultralight backpack with a less sophisticated shoulder harness and hip belt system.
The key design innovation in this revolutionary new suspension system is the fusion of the shoulder harness and the hip belt into single unit that wraps around your torso and waist, molding to your body shape like a bear hug. Throw in an adjustable torso length and hip belt, and there’s no reason why you can’t achieve a perfect fit with this backpack, one that gets the weight off your shoulders and onto your hips.
The Atmos AG 50 has a wireframe that runs around the top, bottom, and sides of the pack, including a horizontal reinforcement bar halfway down the back. The frame is tensioned to create a concave cavity behind the wearer’s back for ventilation and airflow, and then covered with mesh to preserve the air pocket and allow your clothes to dry when you sweat.
The shoulder harness is attached to a pair of webbing straps that run behind the mesh, enabling simple adjustment of the torso length of the pack by moving the back of the shoulder harness up or down to match your torso length. However, if there’s one quibble I have with this pack, it’s that Osprey hasn’t printed torso lengths indicators on the torso length adjustment, so there’s no way of knowing, other than by feel, if you’ve repositioned the shoulder harness so it matches your torso length.
If there’s one thing that hikers consistently get wrong, it’s buying packs that are to short or too long to match their torso length. If Osprey had printed torso length indicators on the adjustable harness, or even documented it in the product manual, they could have solved hiker fit issues once and for all. It’s a missed opportunity to put an end to ill-fitting packs and one that is still so easy to correct if Osprey revises the Atmos AG’s product documentation.
The pre-curved hip belt is also adjustable using Osprey’s Fit on the Fly system which has velcroed extensions built into the hip belt that you can pull out to lengthen it.
Internal Storage and Organization
The Atmos AG is a top-loading, alpine style backpack with a floating top lid, main compartment, rear shovel pocket, and two side water bottle pockets. In addition, the hip belt has two zippered pockets with a solid face fabric that are large enough to store snacks and other odds and ends you want frequent access to.
Floating Top lid
The top lid on the Atmos AG 50 has two zippered pockets. The bottom pocket is larger than the top one and good for storing extra gloves, hat, or snow goggles. The top pocket is smaller and good for storing a map, personal locator beacon, compass, or GPS. The top lid is considered floating because you can raise it up above the main compartment by lengthening the webbing straps that connect it to the top of the pack. You’d do this if you need to wedge more gear between the top lid and the main compartment such as a rope or a bulky sleeping pad (see External Attachment Guide.)
The top lid can also be completely removed on the Atmos AG 50, reducing the pack weight by 5.5 ounces. Osprey provides an alternative fast packing top, called a Flap Jacket, which is a flap of fabric that covers the top of the main compartment to prevent rain entry but does not have any pockets. It’s permanently sewn to the pack and folds under the top lid when not in use. It has two plastic buckles that attach to the vertical webbing straps that are normally used by the top lid. These two buckles are tucked away in corner keeper pockets when the Flap Jacket is not in use.
The main compartment has an internal hydration pocket and hang loop, along with a central hydration port that comes out at the top of the pack between your shoulder blades.
There’s also an optional fabric shelf that you can deploy if you want to create a separate sleeping bag compartment at the base of the back as well as an external zipper that lets you access the compartment’s content. The shelf can be attached to webbing loops inside the pack or folds back when not in use, if you want to use the main compartment as one big storage space.
The Atmos AG 50 has a mesh shovel pocket on the rear of the pack that’s open at the top but secured with a buckle. This pocket is good for storing a climbing helmet, wet items, such as a water filter, or extra layers that you want quick access to without opening the main compartment of your pack.
The side water bottle pockets on the Atmos AG are made out of mesh and have a top opening and a side opening, if you want to be able to access them holster style. When wearing the Atmos AG 50, I can only grab a water bottle and replace it, if it’s holstered sideways, but not if it’s positioned vertically.
Compression System and External Attachment Points
The Atmos AG 50 has two tiers of compression straps, a back and forth strap along the bottom of the pack that runs over the side pockets and a single top strap. While these straps provide good compression, they’re not that great for attaching or securing bulky gear to the side of the pack, like a tent or snowshoes. While using the back and forth bottom strap to lash great to the outside of the pack is awkward at best, the curvature of the frame makes it difficult to attach bulkier gear to the sides of the pack since they are far from rectangular in shape.
While the Atmos AG 50 has dual ice axe loops including shaft holders, it doesn’t have any external lashpoints for rigging your own compression/external attachment system using shock cord on around the perimeter of the shovel pocket, on the bottom of the main compartment, or on the top lid.
If there’s one area of weakness on the Atmos AG 50, it’s the external attachment system. Still it’s not a big deal if you use the pack for day hiking or moderate backpacking trips, but it does limit its utility for winter and more challenging expedition-style hiking. Incidentally, the Osprey Packs Atmos AG 65 does come with optional add-on straps that let you attach additional gear to the back of the pack, so check that backpack out if strapping a bulky sleeping pad, tent, or additional winter gear to the rear of your pack is a priority.
|Make and Model||Weight||Access|
|Gregory Baltoro 65||4 lbs 14.4. oz||Top, front, bottom|
|Gregory Baltoro 75||4 lbs 15.7 oz||Top, front, bottom|
|Gregory Katmai 65||4 lbs 11.8 oz||Top, bottom, side|
|Gregory Paragon 68||3 lbs 11 oz||Top, bottom, side|
|Mountain Hardwear AMG 75||4 lbs 15.4 oz||Top|
|Osprey Aether 65||4 lbs 14.7 oz||Top, front, bottom|
|Osprey Aether Plus 70||5 lbs 8 oz||Top, front, bottom|
|Osprey Aether Pro 70||3 lbs 15 oz||Top|
|Osprey Atmos AG 65||4 lb. 9 oz||Top, bottom, 2 sides|
|REI Trailbreak 60||3 lbs 13 oz||Top, bottom|
Most backpacks have separate hip belts and shoulder harness systems that complement one another but don’t work together as a single unit. That’s why the new Anti-Gravity suspension system used by Osprey Packs Atmos AG 50 is so revolutionary. By integrating these two components into one uniform system that molds to your body shape, with an adjustable torso and hip belt, hikers need never suffer a poor-fitting pack again. While the Atmos AG 50 is a bit heavy at 4 pounds 2 ounces, it’s hard to argue with the comfort that this back provides. If your current overnight backpack doesn’t fit you well or is uncomfortable, I’d encourage you to try on an Osprey Packs Atmos AG 50. It may be the last backpack you ever buy.
- Adjustable torso length and hip belt size
- Superb load to hip transfer
- Integrated frame and hip belt system – unique
- Hip belt pockets are large enough to be useful
- Lidless weight-saving option
- Heavy. Weighs over 4 pounds
- Cluttered with all kinds of zippers and straps
- Difficult to attach bulky gear to the sides or rear of the pack
- Mesh side pockets are prone to ripping
- Weight (size large, tested): 4 pounds 2 ounces
- Volume: 53L (in a size large)/3234 cubic inches
- Maximum recommended load: 40 pounds
- Material: 100-denier x 630-denier nylon dobby/420HD nylon packcloth
Disclosure: The author bought the backpack reviewed here with his own funds.SectionHiker is reader-supported. We only make money if you purchase a product through our affiliate links. Help us continue to test and write unsponsored and independent gear reviews, beginner FAQs, and free hiking guides.