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Hyperlite Mountain Gear Prism 40L vs Outdoor Vitals CS40 Ultra

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

Outdoor Vitals CS40 Ultra is the lighter option — 62 g lighter than the Hyperlite Mountain Gear Prism 40L (7% less weight). If grams matter to you, that is the one to beat.
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Spec Hyperlite Mountain Gear Prism 40L Outdoor Vitals CS40 Ultra
Weight 827 g · 0.827 kg · 1.82 lb 765 g · 0.765 kg · 1.69 lb
Brand Hyperlite Mountain Gear Outdoor Vitals
Category Backpack Backpack
Hyperlite Mountain Gear Prism 40L
827 g

Technical alpine pack in DCH150 Dyneema with crampon pouch, ice tool carry, and removable lid. Load capacity up to 22kg.

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Outdoor Vitals CS40 Ultra
765 g

Ultralight 40L backpack built for ultralight hiking and thru-hiking. Features innovative weight-saving construction that carries 20x its weight.

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Hyperlite Mountain Gear Prism 40L vs Outdoor Vitals CS40 Ultra: which should you buy?

If saving weight is your priority, the Outdoor Vitals CS40 Ultra wins — at 765 g it is 62 g (7%) lighter than the Hyperlite Mountain Gear Prism 40L (827 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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