Outdoor Vitals CS40 Ultra Backpack vs Zpacks Nero Classic 40L
Weight and specs compared for 2026 — and which one to choose.
40L ultralight backpack with carbon fiber frame stays. Weighs 27oz and supports up to 35 lbs with full functionality.
Full details →Frameless ultralight pack in 30L or 40L, built from Dyneema CF fabric. One of the lightest load-carrying packs available for thru-hiking.
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Outdoor Vitals CS40 Ultra Backpack vs Zpacks Nero Classic 40L: which should you buy?
If saving weight is your priority, the Zpacks Nero Classic 40L wins — at 289 g it is 476 g (62%) lighter than the Outdoor Vitals CS40 Ultra Backpack (765 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.