Rain Bird JTV/AS-100 1 Jar Top Anti-Siphon Valve 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. 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.