CamelBak Octane 18X Hydration Pack This expandable pack is perfect for 3+ hours of any adventure Antidote Reservoir features Quick Link System, easy open/close cap, lightweight fillport, dryer arms, center baffling and low-profile design Key Pack Features: Ultra-light materials, center expansion zip, front and back reflectivity, safety whistle Designed to carry extra layer, food, headlamp, trail maps, compass, trekking poles CamelBak Got Your Bak Guarantee: If we build it, we'll Bak it with our lifetime guarantee