The patented Nidel® Model 50HA high flow double check backflow preventer is standard equipment on specified wall faucet models. It is intended for irrigation and outdoor watering and is designed to protect hose connections from backflow contamination in freezing and non-freezing conditions. The Model 50HA automatically drains when the hose is removed and unlike single check vacuum breakers can be field tested for reliability. Woodford® Nidel® Backflow Preventer, High Flow, 3/4 in Nominal, Female Hose Thread x Male Hose Thread, 125 psi, Dual Check Backflow, Brass Body, Domestic