Zpacks Arc Haul Ultra 70L Backpack

The Zpacks Arc Haul Ultra 70L is the largest standard model in the Arc Haul line — a 57 L main body extendable by an 8 L roll-top extension, with a manufacturer-stated total capacity of 70 L. Despite the size, it weighs just 635 g, only a few grams more than the 60 L sibling. The body is Ultra 100X (UHMWPE), a fabric combining high tensile strength with abrasion resistance and low water absorption. The pack closes with a roll-top, backed by a front pocket, two side pockets, a chest strap, and load lifters for fine-tuning the carry. The hip belt is padded, and the 74 × 32 × 24 cm dimensions suggest a pack built for volume rather than compactness. At 9.1 g per liter, it has one of the best weight-to-volume ratios in the Zpacks lineup, a logical choice for long stretches without resupply or winter trips needing a bulkier sleep system. That much volume invites overpacking, though — with no rigid internal structure, packing discipline matters to keep the load centered.