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Gregory Optic 48 vs REI Co-op Flash 55
Weight and specs compared for 2026 — and which one to choose.
REI Co-op Flash 55 is the lighter option — 10 g lighter than the Gregory Optic 48 (1% less weight). If grams matter to you, that is the one to beat.
REI Co-op Flash 55
1,360 g
Lightweight 55L pack designed for trail-focused backpacking.
Full details →Gregory Optic 48 vs REI Co-op Flash 55: which should you buy?
If saving weight is your priority, the REI Co-op Flash 55 wins — at 1,360 g it is 10 g (1%) lighter than the Gregory Optic 48 (1,370 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.