The Mutant 38 pack provides a simple, strong and light solution for short alpine adventures or multiday mountain trips. Its the direct result of testing and feedback from around the vertical world. Thermoformed EVA foam back panel maintains ventilation and minimizes moisture absorption a lightweight, removable framesheet helps stabilize the pack when loaded. Reverse Wrap ErgoPull hipbelt is easy to adjust with a forward-pull motion hipbelt can be tucked out of the way when youre wearing a climbing harness. Thermoformed, contoured back panel provides ventilation and moisture resistance for carrying comfort and snow-shedding capability. Removable foam HDPE framesheet helps stabilize the pack when loaded and doubles as a tri-fold bivy pad. Dual tool loops provide lash points for ice axes or other tools Gorilla Grip patch on the pack fabric resists wear and punctures from sharp tools. Hypalon racking loops on the hipbelt create a durable and unobtrusive gear racking/organization system for climbing equipment. Floating lid with spindrift collar and internal/external pockets allows you to increase pack capacity to 48 liters lid is removable to shed unwanted pounds. Grab handle and 2 reinforced loops at the top of pack create a 3-point haul system for big wall endeavors. Internal sleeve and drink tube exit port accommodate a 3-liter reservoir sold separately for hydration on the go. Z-compression straps cinch down loads for jostle-free carrying and secure skis, poles, or sleeping pads. The Osprey Mutant 38 pack is made of 420-denier Armourlite and 900-denier Armourguard nylon.