Arrowhead brass and plumbing patented nickel-plated, self-draining, anti-siphon vacuum breaker Female fine thread inlet connection by 3/4-in male hose thread outlet Freeze protection combined with health protection from possible contaminated water sources caused by back-siphonage or backflow Water automatically self-drains upon water shutoff, even when attached to a frost-free wall or ground hydrant Backflow caused by back siphonage or back pressure is blocked at the vacuum breaker and automatically drains harmlessly to the ground through the air ports IAPMO listed and ASSE 1011 certified, patent #5,228,471 Genuine Arrowhead part proudly made in the USA 3-year warranty Series Name: Self Draining Vacuum Breaker Type: Vacuum breaker Outlet Diameter: 3/4-in Inlet Thread Type: Threaded Material: Brass Maximum Pressure: 125 PSI Outlet Thread Type: MHT Warranty: 3-year limited Compatible Pipe Material: Brass CA Residents: Prop 65 Warning(s): No Complies with Federal Lead Guidelines: No UNSPSC: 40141700