Orbit Automatic Anti-Siphon Sprinkler Valve Replacement Diaphragm. Made of durable long lasting material. It fits Orbit Anti-Siphon Valve #'s: 57223, 57224, 57321, 57222, 57221, 57623 TV# 533516, 57624 TV# 533544 & 57625. It is used to replace old worn out diaphragms for the Orbit Anti-Siphon Valve. Simply remove old diaphragm & replace.