Tactical Scorpion Gear TSG-25BLD 2.5L Hydration Bladder Reservoir A switch on/off bite valve, convenient for control the flow of water. High quality hydration bladder modeled after the U.S. Military hydration bladder inserts. Perfect replacement for 2.5L  3L bladders Equipped with a tube with a bite valve to drink, so you dont need to hold it to drink. Safe non-toxic TPU material.