This residential and light commercial grade in-line anti-siphon valve replaces Rain Bird and other irrigation valves installed above ground with 1 in. female threaded inlet and outlet. It can be used with any 24 volt AC irrigation timer. Its unique reverse-flow design helps prevent flooding in the event of internal diaphragm failure, keeping the valve closed and saving water. This valve can be applied with all types of watering devices including Rain Bird spray heads (1800, 600), and rotors (22SA, 32SA, 42SA+, 52SA, LG3 and AG5). Use anti-siphon valves in locations where the use of a pressure vacuum breaker (PVB) or a double-check valve is not required by city codes. Check your local city codes to determine what type of valve is required. Anti-siphon valves should be installed at least 6 inches above the highest head on the line, and should never have another valve installed further down from the main line. After installation and before startup, always the flush system of dirt and debris manually using the valve's external bleed screw.