Outdoor Vitals CS40 Ultra vs Zpacks Nero Classic Ultra Backpack
Weight and specs compared for 2026 — and which one to choose.
Ultralight 40L backpack built for ultralight hiking and thru-hiking. Features innovative weight-saving construction that carries 20x its weight.
Full details →Frameless ultralight backpack made from Dyneema Composite Fabric. Minimalist design for SUL hikers. Top-loading with roll-top closure.
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Outdoor Vitals CS40 Ultra vs Zpacks Nero Classic Ultra Backpack: which should you buy?
If saving weight is your priority, the Zpacks Nero Classic Ultra Backpack wins — at 289 g it is 476 g (62%) lighter than the Outdoor Vitals CS40 Ultra (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.