Have you taken your hose off had a splash-back of water? The 50HA series protects from splash-back!

The Woodford Model 50 Auto-Drain Double Check Backflow Preventer is 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 checks move as one to open a path through the valve allowing water to drain completely and prevent freezing. Available Finishes: Chrome Plated and Brass 

Integral Device:
50HA replaces VB222 and is standard on Model C22 B22 27 and 30  (shown below)
50HF standard on Model 26 Y2 H34 B26 and Y95

NOTICE: These products as with all 1011 1019 1052and 1053 ASSE listed devices are not to be subjected to continuous water pressure. Replacement is recommended every 3-5 years. After use turn device to open drain vents or faucet may freeze and burst.