Arcteryx made the Acrux 65 Backpack with 4090cu in of waterproof storage and a low 4lb 3oz regular size weight for alpine climbers casting off on massive 4-day-or-more routes. Seam-sealed VaporTight fabric and a roll-top closure make the Acrux 65 backpack completely impermeable to any mountain storm. The lid, dual aluminum frame stays, and molded Binary Hippods are removable for your ultralight summit push. Pre-molded shoulder straps add to this Arcteryx packs comfort, but its the ability to keep your sleeping bag and down jacket dry for five days straight that makes the Acrux a favorite. Available for US shipment only.