ARROWHEAD BRASS & PLUMBING BACK FLOW PREVENTER * Back Flow Preventer. * Non Anti-Siphon. * 3/4 Hose Thread. * For Non-Freeze Areas Hose Bibbs. * Laundry Tubs. * Utility Sinks. * Not To Be Used On Standard Frost Proof Hydrant. * Vacuum Breaker 5/8 Hose Thread. * Lead Free.