FEBCO 765EBV 1" Pressure Vacuum Breaker with Ball Shut-Off Valve. This 1 inch pressure vacuum breaker backflow preventer is used to protect against health hazard and non-hazard backsiphonage of toxic or non-toxic liquids in industrial plants, cooling towers, laboratories, laundries, swimming pools and irrigation systems. It has a bronze body, spring loaded check valve, air relief valve with opening port, two resilient seated shutoffs and test cocks, and NPT end connections. This assembly meets the specifications of the USC FCCCHR Manual. The maximum working pressure is 150 psi (10.3 bar) and temperature range is 32 degrees F to 140 degrees F (0 degrees C to 60 degrees C).