Black Diamond Speed 40 vs REI Co-op Flash 45

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

Black Diamond Speed 40 is the lighter option — 10 g lighter than the REI Co-op Flash 45 (1% less weight). If grams matter to you, that is the one to beat.

Spec	Black Diamond Speed 40	REI Co-op Flash 45
Weight	1,180 g · 1.180 kg · 2.60 lb	1,190 g · 1.190 kg · 2.62 lb
Brand	Black Diamond	REI Co-op
Category	Backpack	Backpack

Black Diamond Speed 40

1,180 g

Lightweight 40L alpine pack with removable framesheet.

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REI Co-op Flash 45

1,190 g

Lightweight 45L versatile backpacking pack.

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Black Diamond Speed 40 vs REI Co-op Flash 45: which should you buy?

If saving weight is your priority, the Black Diamond Speed 40 wins — at 1,180 g it is 10 g (1%) lighter than the REI Co-op Flash 45 (1,190 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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