Orbit 1" Underground Sprinkler Anti-Siphon Valve. Made from durable PVC construction, this valve effectively prevents contaminants from entering the main water supply, ensuring the safety of your drinking water. It features a precise flow control adjustment for customized watering needs and a ratchet handle that prevents over-tightening damage. Required in many municipalities, this anti-siphon valve connects with 3/4 inch threaded pipe.