Outdoor Vitals CS40 Ultra vs Zpacks Nero Classic 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 →Ultralight frameless Dyneema Composite backpack, just 289g. Roll-top closure with mesh side pockets. Ideal for SUL hikers carrying under 10 lbs base weight.
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Outdoor Vitals CS40 Ultra vs Zpacks Nero Classic Backpack: which should you buy?
If saving weight is your priority, the Zpacks Nero Classic 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.