Woodford Add-On 3/4 in. Hose Thread Brass Double-Check Backflow Preventer

Add-on to any 3/4 in. hose connection. UPGRADE to the 50H. 3/4 in. hose thread. The first ASSE 1052 approved automatic draining double-check backflow preventer. When a hose is removed from a Model 50 equipped wall faucet or yard hydrant, two linked but independent check valves automatically move as one to open a path through the valve allowing water to drain completely and prevent freezing.