The CamelBak Crux reservoir on/off valve is designed to pair with the Big Bite valve, allowing you to easily toggle it off during transport for added security. This valve does not come with a Big Bite valve and is not compatible with older style Antidote or OMEGA reservoirs. The ergonomic on/off valve makes it easy to grip and toggle the tube while on the move. Turn off the water flow from the CamelBak Crux Reservoir when transporting. The 45-degree bend of the Big Bite Valve positions it perfectly for easy drinking. The patented Big Bite Valve mouthpiece offers hands-free hydration and is ideal for high-performance situations. It self-seals after each drink to eliminate annoying drips.