1 in. FPT Auto Inline ValveLid screws will work with flat head or Philips screwdriver, as well as a 5 16 socket Spring attaches to diaphragm to reduce the chances of losing it Captured plunger solenoid Diaphragm post for easy realignment 1 in. female threaded valve Inline valve works with standard residential 24 Volt sprinkler systems For outdoor use with cold water only For irrigation applications only Compatible with all 24V systems Soft close design reduces water hammer