Woodford 3/4 in. Thread X 3/4 in. Thread Brass Backflow Preventer

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.