REI Co-op Flash 45 vs Zpacks Nero Classic Ultra Backpack

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

Zpacks Nero Classic Ultra Backpack is the lighter option — 901 g lighter than the REI Co-op Flash 45 (76% less weight). If grams matter to you, that is the one to beat.

Spec	REI Co-op Flash 45	Zpacks Nero Classic Ultra Backpack
Weight	1,190 g · 1.190 kg · 2.62 lb	289 g · 0.289 kg · 0.64 lb
Brand	REI Co-op	Zpacks
Category	Backpack	Backpack

REI Co-op Flash 45

1,190 g

Lightweight 45L versatile backpacking pack.

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Zpacks Nero Classic Ultra Backpack

289 g

Frameless ultralight backpack made from Dyneema Composite Fabric. Minimalist design for SUL hikers. Top-loading with roll-top closure.

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REI Co-op Flash 45 vs Zpacks Nero Classic Ultra Backpack: which should you buy?

If saving weight is your priority, the Zpacks Nero Classic Ultra Backpack wins — at 289 g it is 901 g (76%) 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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