Rugged and durable Water Beast™ material, leak-proof screw-cap, insulated PureFlow™ tube, patented Big Bite™ Valve, HydroLink™ Exit Port and Drink Port, HydroLock™ one-handed flow control . . KEY PACK FEATURES: . . Sternum Strap for added stability, Closed cell insulation and neoprene tube cover keeps water cool or warm for hours, Includes HydroLink Modular Connection System with positive shut-off HydroLock™, Exterior fillport with ergonomic handle for filling on the go, Quick-release shoulder straps unclip for easy removal, Tough, abrasion-resistant 1000D Cordura® Fabric exterior, Convenient Velcro strap management