Designed specifically for the next-gen Hydraulics Bite Valve, this cover keeps the mouthpiece free from dirt and dust on the trail. Protects bite valve with a twist locking system to turn on/off flow of liquid. Compatible with Hydraulics Reservoir and Hydraulics LT Reservoir. Features a new on/off lever that is thumb-operable and easy to regulate with one hand. Updated parts ensure a more secure hose capture.