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Osprey Atmos AG 65 vs Zpacks Nero Classic 40L

Weight and specs compared for 2026 — and which one to choose.

Zpacks Nero Classic 40L is the lighter option — 1,891 g lighter than the Osprey Atmos AG 65 (87% less weight). If grams matter to you, that is the one to beat.
Spec Osprey Atmos AG 65 Zpacks Nero Classic 40L
Weight 2,180 g · 2.180 kg · 4.81 lb 289 g · 0.289 kg · 0.64 lb
Brand Osprey Zpacks
Category Backpack Backpack
Osprey Atmos AG 65
2,180 g

Full-featured 65L pack with Anti-Gravity suspension. Ideal for extended trips.

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Zpacks Nero Classic 40L
289 g

Frameless ultralight pack in 30L or 40L, built from Dyneema CF fabric. One of the lightest load-carrying packs available for thru-hiking.

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Osprey Atmos AG 65 vs Zpacks Nero Classic 40L: which should you buy?

If saving weight is your priority, the Zpacks Nero Classic 40L wins — at 289 g it is 1,891 g (87%) lighter than the Osprey Atmos AG 65 (2,180 g). That said, the heavier option may justify the extra grams with more capacity, durability or comfort, so weigh the trade-off against how you'll use it.

See where both rank against everything else in this category on the lightest backpack page, or browse the full gear weight database.

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