Lid screws will work with flat head or phi lips 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; 3/4 Inch female-threaded valve; The Inline valve works with standard residential 24 Voltsprinkler systems; For outdoor use with cold water only