The CamelBakA(R) Crux(TM) reservoir on/off valve pairs with the Big Bite valve, shutting off the water flow for added security during transport. Features and Specs Features Ergonomic on/off valve make it easy to grip tube and toggle while you&';re on the move Turn off water flow from CamelBak Crux Reservoir during transport 45-degree bend perfectly positions the Big Bite Valve for easy drinking The patented Big Bite Valve mouthpiece offers Hands-Free Hydration and is ideal for any high-performance situations. Self-seals after each drink to eliminate annoying drips. Specs BPA/BPS/BPF Free Material: Polypropylene/ LDPE (on/off valve)