Osprey Stratos 36 vs REI Co-op Flash 55

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

Osprey Stratos 36 is the lighter option — 50 g lighter than the REI Co-op Flash 55 (4% less weight). If grams matter to you, that is the one to beat.

Spec	Osprey Stratos 36	REI Co-op Flash 55
Weight	1,310 g · 1.310 kg · 2.89 lb	1,360 g · 1.360 kg · 3.00 lb
Brand	Osprey	REI Co-op
Category	Backpack	Backpack

Osprey Stratos 36

1,310 g

Ventilated 36L day and overnight pack with AirSpeed suspension.

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REI Co-op Flash 55

1,360 g

Lightweight 55L pack designed for trail-focused backpacking.

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Osprey Stratos 36 vs REI Co-op Flash 55: which should you buy?

If saving weight is your priority, the Osprey Stratos 36 wins — at 1,310 g it is 50 g (4%) lighter than the REI Co-op Flash 55 (1,360 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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