High Sierra Longshot 70 Hydration Pack Mini-Hex Ripstop/Mini-Weave Duralite Large, multi-compartment design Separate, side-access hydration reservoir compartment makes it easy to access your water supply 2-liter hydration system has a wide opening reservoir for easy filling and cleaning. System is BPA free and antimicrobial Hands-free reservoir pressure valve Insulated water tube cover helps to prevent water from freezing in tubefreezing in the tube