← Gear database

Six Moon Designs Fusion 55 vs Zpacks Arc Haul Ultra 40L

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

Zpacks Arc Haul Ultra 40L is the lighter option — 82 g lighter than the Six Moon Designs Fusion 55 (13% less weight). If grams matter to you, that is the one to beat.
shopping_cart Check today's price on Amazon
Spec Six Moon Designs Fusion 55 Zpacks Arc Haul Ultra 40L
Weight 622 g · 0.622 kg · 1.37 lb 540 g · 0.540 kg · 1.19 lb
Brand Six Moon Designs Zpacks
Category Backpack Backpack
Six Moon Designs Fusion 55
622 g

Ultralight 55L frameless Dyneema pack.

Full details →
Zpacks Arc Haul Ultra 40L
540 g

Dyneema 40L pack at 540g. Compact version of Arc Haul for minimalist backpacking setups.

Full details →

HikeLoad is reader-supported. As an Amazon Associate we earn from qualifying purchases, at no extra cost to you. Learn more.

Six Moon Designs Fusion 55 vs Zpacks Arc Haul Ultra 40L: which should you buy?

If saving weight is your priority, the Zpacks Arc Haul Ultra 40L wins — at 540 g it is 82 g (13%) lighter than the Six Moon Designs Fusion 55 (622 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.

More backpack comparisons