Rain Bird JTV/ASF-100 1 Jar Top Anti Siphon Valve With Flow Control Type: Accessories Features: Easy cleaning and maintenance with one-piece jar-top lid. Rain Bird exclusive fail-safe design. External bleed to manually flush system of dirt and debris during installation and system start up. Heavy duty, professional design for a life-time of trouble-free operation. Flow control models regulate the flow of water to sprinklers to avoid misting. Operates automatically with any standard 24 volt sprinkler timer. Vacuum breaker prevents backflow contamination to keep drinking water safe. Meets I.A.P.M.O. listing specifications.