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Osprey Exos 48 vs REI Co-op Flash Air 50

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

REI Co-op Flash Air 50 is the lighter option — 412 g lighter than the Osprey Exos 48 (32% less weight). If grams matter to you, that is the one to beat.
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Spec Osprey Exos 48 REI Co-op Flash Air 50
Weight 1,280 g · 1.280 kg · 2.82 lb 868 g · 0.868 kg · 1.91 lb
Brand Osprey REI Co-op
Category Backpack Backpack
Osprey Exos 48
1,280 g

Lightweight 48L thru-hiking pack with excellent ventilation.

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REI Co-op Flash Air 50
868 g

Ultralight 50L pack with 3D contoured hip belt and ventilated back panel. Made from PFAS-free UHMWPE fabric with DWR coating.

Full details →

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Osprey Exos 48 vs REI Co-op Flash Air 50: which should you buy?

If saving weight is your priority, the REI Co-op Flash Air 50 wins — at 868 g it is 412 g (32%) lighter than the Osprey Exos 48 (1,280 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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