P RV VACUUM BREAKER CHECK VALVE: Suitable for B&B 571 check valves which are part of a black water tank flushing system and are installed between the fresh water inlet and the tank flusher. The vacuum breaker can help black tank water for mixing with grey water to ensure clean and healthy water UPGRADED CONSTRUCTION: This 571-VAC-CHK-A RV Vacuum Breaker Check Valve is made of brass and can withstand 8-125 PSI of water pressure. Less susceptible to freezing and cracking in cold climates, better performance and longer service life than plastic EASY INSTALLATION: Can simply be fitted to a caravan's black water tank flushing system and must be installed 6” above the highest point of any item connected to the waste water tank where the flusher is fitted. If you are unsure how to install the check valve, it is recommended to ask a professional plumber VERSATILE APPLICATION: This vacuum breaker check valve is suitable for all models of caravans, campers, preventing the contents of the black water tank from siphoning back into the RV freshwater system, travel trailers and motels and is a reliable alternative to ruptured or leaking check valves RELIABLE AND EFFICIENT: When your RV check valve leaks while flushing your black water tank, you can simply replace the leaking RV vacuum breaker check valve. Say goodbye to leaks in your water. Making your caravan life more convenient and comfortable