Gear Review: Osprey Manta AG 20 Daypack

Osprey Manta AG 20
Osprey Manta AG 20

Osprey Manta AG 20
$155, 20L/1,220 c.i., 2 lbs. 11 oz.
One size

How much stuff goes into your daypack? If you routinely carry upwards of 15 pounds or more (including the pack’s empty weight) on dayhikes, unless you possess a spine of steel, it really makes sense to get a pack designed for comfort with that kind of payload. When Osprey brought its groundbreaking Anti-Gravity suspension to the men’s Manta and women’s Mira daypacks this year, I decided to take the Manta AG 20 out for some trail mileage, including a 14-mile, 3,000-foot dayhike of 11,049-foot Telescope Peak in California’s Death Valley National Park to see how it measures up.

Osprey Manta AG 20 harness.
Osprey Manta AG 20 harness.

The signature feature of Osprey’s Anti-Gravity (AG) packs is a trampoline-style panel of lightweight, tensioned mesh extending from the top of the back panel to the hipbelt, enwrapping your back and hips while allowing plenty of air movement across your back. In the Manta and Mira, a wire perimeter frame flexes slightly, allowing the pack to move somewhat with your body while retaining its shape with significant weight inside.

For a system designed for larger backpacks—I think it performs exceptionally well in the men’s Atmos AG and women’s Aura AG packs—it crosses over very effectively to a medium-size daypack like the Manta 20. Osprey simply dialed back the amount of padding and support used in the larger backpacks—especially in the hipbelt, which in the Manta and Mira flexes but doesn’t sag or collapse with 20 pounds inside the pack. Dual side compression straps not only shrink undersized loads to prevent contents from shifting, but the lower compression straps double as stabilizers, pulling the pack bottom in to help direct most of the weight onto your hips, where you want it. Soft, perforated foam lets the shoulder straps ventilate your body heat and sweat.

Osprey Manta AG 20.
Osprey Manta AG 20.

There is a slight side-to-side motion of the pack when you hike, from the natural, up-and-down rotation of your hips (something you’ll see in many packs of all sizes, unless they have a pivoting mechanism in the hipbelt, a rare feature). But the pack’s frame, suspension, and compression otherwise minimize that kind of movement.

Available only in one torso size, the Manta 20 fits my 18-inch torso well and probably will fit male torsos roughly 17 to 20 inches. Although the concave shape to the back panel reduces the potential interior capacity, I think it’s a small sacrifice for the ventilation and comfort gained, and the pack still has the capacity for an all-day, three-season hike, as long as your clothing isn’t too bulky or you’re not carrying a huge amount of water. If you need more volume, there’s the Manta AG 36 ($175) and Manta AG 28 ($165), both of which, unlike the Manta 20, come in two sizes. The women’s Mira AG comes in 34L ($175), 26L ($165), and 18L ($155).

Instead of a lid pocket, you open the Manta’s main compartment with a convenient, two-way, clamshell zipper that extends about halfway down the pack bag, giving adequate access without letting contents spill out. Behind it is a separate, zippered bladder compartment for easily refilling water without unloading other contents; and the Manta and Mira packs come with a functional and durable, 2.5-liter Osprey Hydraulics bladder with a locking mouthpiece and magnetized attachment to the sternum strap. In addition, there’s a vertical, zippered front pocket with an internal mesh organizer to hold smaller items, two roomy hipbelt pockets, a sunglasses pocket, and mesh pockets on the side for bottles and on the front for a jacket.


Other smart features include a trekking poles attachment on the left shoulder strap which let me quickly stash trekking poles on the go (convenient for photography or scrambling), a single gear loop on the hipbelt, front loops for a helmet and light (this would make an excellent bike-commuting pack), and an integrated rain cover in a zippered pocket on the bottom. The upper compression straps have quick-release buckles for attaching objects to the pack. The 210-denier high-tenacity nylon in the body and bottom does not make it the most bulletproof daypacks out there, but comparable to many better competitors.

It’s also a good carry-on size: I used it flying cross-country and wearing it on subway trains, and I fit all I needed for a week inside it, negating the need to check luggage.

While it’s a little more daypack than I would choose with lighter loads, when you want a pack for hikes and adventures when you have to haul 15 to 25 pounds all day, there may not be a more comfortable choice than the Manta and Mira.

BUY IT NOW You can support my work on this blog by clicking one of these links to purchase an Osprey Manta 20 at or an Osprey Mira 18 daypack at

See all of my reviews of daypacks I like and my stories “5 Tips For Buying the Right Backpack” (which applies to daypacks) and all of my reviews of hiking gear.

See also my stories:
The Simple Equation of Ultralight Backpacking: Less Weight = More Fun
Buying Gear? Read This First
5 Tips For Spending Less on Hiking and Backpacking Gear
Ask Me: How Do We Begin Lightening Up Our Backpacking Gear?

NOTE: I tested gear for Backpacker Magazine for 20 years. At The Big Outside, I review only what I consider the best outdoor gear and apparel. See all of my Gear Reviews at The Big Outside.

—Michael Lanza

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2 thoughts on “Gear Review: Osprey Manta AG 20 Daypack”

    • Hi Derrick, as I wrote in the review: “The signature feature of Osprey’s Anti-Gravity (AG) packs is a trampoline-style panel of lightweight, tensioned mesh extending from the top of the back panel to the hipbelt, enwrapping your back and hips while allowing plenty of air movement across your back.”

      That’s the major improvement and change.