Explore remote outdoor locations and stay hydrated with the CamelBak Antidote Reservoir. This portable and self-contained hydration system easily fits into most backpacks, and its 38"-long delivery tube provides easy access to your water supply when you' re on the go. Its unique design features three points of liquid flow control. The first one is an on/off valve, located at the base of the bag, useful for sealing contents during transport. The second is the Ergo HyrdroLock, which shuts down the flow in the event of accidental pressure on the bag during strenuous activity. Third is the Big Bite Valve, located at the tip of Pure Flow delivery tube, which allows you to control the flow of water while you are drinking. The silicone mouthpiece is soft to bite, and auto-seals as soon as you release it, allowing hands-free operation and preventing leaks and drips. Just gently squeeze the mouthpiece, and the internal valve will open to allow the flow of water when you need it.