Atom Packs Pulse EP50 vs REI Co-op Flash 55

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

Atom Packs Pulse EP50 is the lighter option — 680 g lighter than the REI Co-op Flash 55 (50% less weight). If grams matter to you, that is the one to beat.

Spec	Atom Packs Pulse EP50	REI Co-op Flash 55
Weight	680 g · 0.680 kg · 1.50 lb	1,360 g · 1.360 kg · 3.00 lb
Brand	Atom Packs	REI Co-op
Category	Backpack	Backpack

Atom Packs Pulse EP50

680 g

UK-made 50L ultralight thru-hiking pack with a carbon hooped frame and EcoPak fabric, carrying loads up to ~14kg comfortably.

Check price Full details →

REI Co-op Flash 55

1,360 g

Lightweight 55L pack designed for trail-focused backpacking.

Full details →

Atom Packs Pulse EP50 vs REI Co-op Flash 55: which should you buy?

If saving weight is your priority, the Atom Packs Pulse EP50 wins — at 680 g it is 680 g (50%) 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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