Univ AntiSiphon Valve

Universal, Hose Bib Anti-Siphon Valve, Helps Prevent The Backflow Of Contaminants From The Garden Hose Entering The Home Water Supply, Fits Standard Outdoor Hose Faucets, 3/4" Female Inlet x Male Hose Thread Outlet, Prevents Outside Water From Siphoning, Through An Outside Faucet & Contaminating The Drinking Water.