Hyperlite Mountain Gear Southwest 55 Backpack vs REI Co-op Flash 55
Weight and specs compared for 2026 — and which one to choose.
Robust ultralight pack with Dyneema Composite Hybrid fabric and two aluminum stays. Ideal for technical terrain and variable weather conditions.
Full details →Lightweight 55L pack designed for trail-focused backpacking.
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Hyperlite Mountain Gear Southwest 55 Backpack vs REI Co-op Flash 55: which should you buy?
If saving weight is your priority, the Hyperlite Mountain Gear Southwest 55 Backpack wins — at 850 g it is 510 g (38%) 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.