Camelback arete 18 hydration pack minimalist ultra light hydration pack for the final ascent or reservoir sleeve to throw in a larger multi day pack you get both with the ar te 18 key pack features converts to reservoir sleeve secure stash pocket with key clip removable sternum strap ultra light materials highly compressible designed to carry extra layers food headlamp trail map antidote reservoir features 14 turn easy openclose cap lightweight fillport dryer arms ce