From the Manufacturer
Rain Bird manufactures only the highest quality In-Line valves. Use In-Line valves in locations where the use of a pressure vacuum breaker (PVB) or a double-check valve is required by city codes to protect against back flow. Check your local city codes to determine what type of valves are required. In-Line valves are installed below ground in a valve box down stream from the main line from a PVB or doublecheck valve. In-Line valves will not prevent back flow on their own, they need the help of a back flow prevention device. Features and benefits: Buna-N diaphragm offers superior performance in harsh water environments. Reliable, non-clogging design. Reverse Flow design reduces stress on diaphragm for dependable operation. In-line design minimizes pressure loss of dirt and debris during installation and system start-up. Operates automatically or manually with manual bleed screw. Works with any standard sprinkler timer. Designed for below-ground installation, out of sight and away from playful hands. Valve color may vary from gray and black to all black.
3/4" Electric Automatic In-Line Valve, Flow Control Adjustment & Manual On/Off, Most Commonly Used On Systems Utilizing Un-Metered Water Sources.