“The most comfortable backpack I’ve worn yet.” A bold statement for sure, but after testing the recently-released Osprey Atmos AG carrying loads on multiple trips, it’s one I make without reservation.

The Atmos AG is a remarkable pack that literally suspends every strap and weight retention system away from your shoulders, back, and hips. What contacts your body is a thin mesh that hugs close and allows for incredible ventilation while supporting weight evenly over a vast surface area.

We’ve never tested anything like it before, and it really works.

The Gear: Osprey Atmos AG 50

Price/Available: Available now for $230 at REI

First Impressions: As I put the pack on for the first time it seemed more like a well-tailored suit than a hiking pack. It forms to the body very well, especially the hip belt, which literally latches onto you. The pack even stayed on my body with no shoulder straps and the hip belt unbuckled! At the GJ office we’ve nicknamed it the “hip-hugger pack.”

Where to Test: From overnights to long stretches on the trail, and traveling.

Who’s it for: Comfort-loving backpackers, anti-luggage travelers, and sweaty people.

Putting it to the Test: Over the weeks of testing I fell in love with the 3D suspension. It gives the feeling that the backpack is a part of you instead of attached to you. The 26lbs of gear, food, and, water I carried for a Superior Hiking Trail backpacking trip felt effortless.

The weight settled nicely on my hips, and as the miles went by it remained comfortable. It took no toll on my shoulders or hips; the innovation in the Atmos AG delivers.

When traveling I easily fit all of my gear into the pack for an 8-day trip to Costa Rica. It held up on the plane, buses, and treks to hostels. I used it on treks in the jungle and the beach.

For fun, back at home, I decided to take the backpack onto a trampoline. I wanted to see if it would stay close to my body while jumping, spinning, and flipping. To my surprise it did!

Sweaty Shirt No More: Back sweat is a longtime foe of backpack-wearers everywhere. Ventilated packs have been around for years but the decreased load carrying stability has always offset that breezy feeling.

A mile into my Superior Hiking Trail backpacking trip I realized, for the first time ever, my back was cold. I stopped for a second and thought, “Wow this pack really works!” Miles later on our 65-degree, sunny and windy trip, my back warmed up, but even at the end of the day I didn’t have that soaked-shirt feeling.

Osprey recognized the problem in 1976 and was one of the first companies to introduce breathable mesh in its backpack line. 10 years ago the company released its first ventilated Atmos backpack. Now in the fourth generation, the completely redesigned Atmos AG is a premier ventilated backpack on the market.

Boring but Important: The Atmos AG comes in 2 sizes, 50L and 65L. The 50-liter version: weighs 4.0lbs, carries 25-40lbs, costs $229.95. The 65-liter version: weighs 4lbs 6oz, carries 30-50lbs, costs $259.95.

Anti-Gravity? The Atmos and Aura backpacks both have the something called Anti-Gravity Suspension — a single piece of stretchy mesh fabric spans from the top of the back down into the hip belt. It looks odd at first, but it feels awesome and works great.

The mesh in the lower back and hip belt is firm yet stretchy, giving it a springy property that really hugs your waist. It never felt unstable when hiking, traveling, or even while jumping on the trampoline.

Important Specs:

Removable “floating” top lid with flap jacket cover underneath

Top loading with zippered access from the bottom

Shoulder harness adjusts to your torso size for better fit

Fit on the Fly Hip Belt extends hip belt easily

Compression straps

Trekking pole attachments

Two Ice tool loops

Front mesh pocket

Dual entry mesh side pockets

Hip belt pockets

Internal reservoir sleeve

Awesome: After multiple tests this pack stands out as the most comfortable I’ve worn. Everything from strap adjustment, to water bottle retrieval, to stowing trekking poles can all be done while hiking so I didn’t have to stop. The shoulder straps are plush and comfortable.

Flaw: The flapjack lid seems to get in the way when the top lid is on. The 50L pack seems to have every bell and whistle except sleeping pad straps. The compression straps worked fine for lashing gear but I was surprised at the omission. The 65L version does have sleeping pad straps. Also, at 4 pounds or more when empty, the pack is on the heavy side and is probably overkill for lighter loads.

Who should buy it: Backpackers and travelers looking for a ventilated pack that fits well, distributes weight properly, and has the ability to carry heavier loads.

Women’s Pack: Osprey has a women’s AG series as well with similar specs — the Aura AG 50 and 65 models.

Made In: Vietnam

Contact Brand: Osprey