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Osprey Atmos AG 65 vs REI Co-op Flash 45

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

REI Co-op Flash 45 is the lighter option — 990 g lighter than the Osprey Atmos AG 65 (45% less weight). If grams matter to you, that is the one to beat.
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Spec Osprey Atmos AG 65 REI Co-op Flash 45
Weight 2,180 g · 2.180 kg · 4.81 lb 1,190 g · 1.190 kg · 2.62 lb
Brand Osprey REI Co-op
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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REI Co-op Flash 45
1,190 g

Lightweight 45L versatile backpacking pack.

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Osprey Atmos AG 65 vs REI Co-op Flash 45: which should you buy?

If saving weight is your priority, the REI Co-op Flash 45 wins — at 1,190 g it is 990 g (45%) 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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