Osprey Hydraulics Bite Valve Cover It Was a Cover-Up Nothing is worse than getting dirt and debris in your bite valve. Luckily, you can cover it up. The Osprey Hydraulics Bite Valve Cover is designed specifically for the next-gen Hydraulics Bite Valve. This cover keeps the mouthpiece free from dirt and dust on the trail. Features Designed for the next-gun Hydraulics Bite Valve Keeps the mouthpiece free from dirt and dust on the trail Bite valve not included | Osprey | Hydraulics Bite Valve Cover Valve Cover Hydration Pack