Watts 800M4-FR 1/2" Vacuum Breaker

Watts 800M4 1/2 inch bronze freeze resistant pressure vacuum breaker backflow preventer helps prevent the reverse flow of polluted water from entering into the potable water supply. The assembly has a bronze body,Êsilicone rubber check valve disc, plastic check valve seat, stainless steel springs, a bonnet with silicone rubber O-ring seal, a lightweight plastic disc float, a built-in relief valve to protect the internal components and the body from freezing, tee handle shutoffs, and test cocks.