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Hyperlite Mountain Gear Pemi 15 Running Vest vs REI Co-op Flash 55

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

Hyperlite Mountain Gear Pemi 15 Running Vest is the lighter option — 1,009 g lighter than the REI Co-op Flash 55 (74% less weight). If grams matter to you, that is the one to beat.
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Spec Hyperlite Mountain Gear Pemi 15 Running Vest REI Co-op Flash 55
Weight 351 g · 0.351 kg · 0.77 lb 1,360 g · 1.360 kg · 3.00 lb
Brand Hyperlite Mountain Gear REI Co-op
Category Backpack Backpack
Hyperlite Mountain Gear Pemi 15 Running Vest
351 g

Running vest using ALUULA Graflyte fabric for ultralight trail runners.

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REI Co-op Flash 55
1,360 g

Lightweight 55L pack designed for trail-focused backpacking.

Full details →

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Hyperlite Mountain Gear Pemi 15 Running Vest vs REI Co-op Flash 55: which should you buy?

If saving weight is your priority, the Hyperlite Mountain Gear Pemi 15 Running Vest wins — at 351 g it is 1,009 g (74%) 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.

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