Durston Gear Kakwa 40 vs REI Co-op Flash 45

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

Durston Gear Kakwa 40 is the lighter option — 395 g lighter than the REI Co-op Flash 45 (33% less weight). If grams matter to you, that is the one to beat.

Spec	Durston Gear Kakwa 40	REI Co-op Flash 45
Weight	795 g · 0.795 kg · 1.75 lb	1,190 g · 1.190 kg · 2.62 lb
Brand	Durston Gear	REI Co-op
Category	Backpack	Backpack

Durston Gear Kakwa 40

795 g

Ultralight 40L internal-frame thru-hiking pack in Ultra 200X fabric, with a hollow aluminum U-frame and 15L of external storage.

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REI Co-op Flash 45

1,190 g

Lightweight 45L versatile backpacking pack.

Full details →

Durston Gear Kakwa 40 vs REI Co-op Flash 45: which should you buy?

If saving weight is your priority, the Durston Gear Kakwa 40 wins — at 795 g it is 395 g (33%) 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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