Toro 1" Anti-Siphon Valves provide the features and benefits of our popular jar top valves and atmospheric backflow preventer in one easy to install device. These valves are typically installed 6" to 12" (15.2 cm to 30.5 cm) above the highest sprinkler making them easy to access and install. The threaded bonnet jar top system enables fast and easy servicing. Toro Anti-siphon Valves feature flow control making it possible to fine-tune the amount of water pressure going to each individual zone, reducing misting and fogging at the sprinkler and saving water.