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REI Co-op Flash Air 50 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 — 579 g lighter than the REI Co-op Flash Air 50 (67% less weight). If grams matter to you, that is the one to beat.
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Spec REI Co-op Flash Air 50 Zpacks Nero Classic Ultra Backpack
Weight 868 g · 0.868 kg · 1.91 lb 289 g · 0.289 kg · 0.64 lb
Brand REI Co-op Zpacks
Category Backpack Backpack
REI Co-op Flash Air 50
868 g

Ultralight 50L pack with 3D contoured hip belt and ventilated back panel. Made from PFAS-free UHMWPE fabric with DWR coating.

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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 Air 50 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 579 g (67%) lighter than the REI Co-op Flash Air 50 (868 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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