The "Alpha" hydration system boasts many features including an extremely durable 120 oz. collapsible bottle bladder. The bladder is a one-piece, flexible blow-molded bottle with an integral threaded neck that can fit a standard M-1 military canteen cap. The hyperflow bite valve delivers a high flow rate when drinking, but drip free when not in use. Bladder is capable of withstanding freezing temperatures. Sanitation is a breeze with our bottle designed bladder, just rinse and air dry. The pack fits comfortably with 2" adjustable, shoulder and chest straps, quick release buckles and D-ring attachment points. The nylon-insulated pack has a 45 cubic inch zippered, cargo compartment and MOLLE web system.