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Hyperlite Mountain Gear Southwest 55 vs REI Co-op Flash Air 50

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

No winner on weight yet. The recorded weights have not both been verified on the same basis. Size, included parts and single-item versus pair weights can differ. Check the linked sources before choosing a replacement.

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Spec Hyperlite Mountain Gear Southwest 55 REI Co-op Flash Air 50
Weight 680 g · 0.680 kg · 1.50 lb 868 g · 0.868 kg · 1.91 lb
Brand Hyperlite Mountain Gear REI Co-op
Category Backpack Backpack
Hyperlite Mountain Gear Southwest 55
680 g

Ultralight Dyneema 55L pack for serious gram-counters.

See it in your base weight → Full details →
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.

See it in your base weight → Full details →

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Hyperlite Mountain Gear Southwest 55 vs REI Co-op Flash Air 50: which should you buy?

The listed weights alone are not enough to choose between these products. Confirm the size, included parts and weight basis against each source; choose equipment for the function and fit you need.

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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