Zpacks Arc Haul Ultra 40L Backpack

The Zpacks Arc Haul Ultra 40L is a framed ultralight pack for long-distance hiking, built around a curved carbon Arc Frame that holds the back panel away from your body, creating an air channel for ventilation. The body is Ultra 100X fabric — UHMWPE laminated to a waterproof backing with taped seams — effectively waterproof without a rain cover. At 602 g and 40 L (28 L main plus 8 L external pocket), it's rated to 18 kg. The frame is fixed, back length is adjustable, and the hip belt is padded and interchangeable, letting you dial in fit more precisely than a one-size belt. Closure is roll-top, backed by a front stretch-mesh pocket, two side pockets, side compression straps, and trekking pole holders. The fabric carries no DWR coating and is PFAS-free. This pack suits trips of six or more nights, where volume and weight matter together. Its weight-per-liter figure of 15.1 g/L is solid but not extreme — hikers chasing the lowest base weight will look at frameless designs instead, trading away the higher load rating.