High Sierra Kahuna 70 Pack (Chipotle, Graphite) Main compartment, with thermo-silver insulation, has a 2-liter water reservoir and a bicycle pump sleeve. Reservoir opening is easy to fill and accepts most brands of water filters. Hands-free reservoir pressure valve. Tuck-away mesh sport flap is hidden in a zippered pocket and holds a helmet. Insulated water tube cover prevents water from freezing in the tube.