This check valve for a 3/4" port (1" flange) is compatible with the ports 1203R and 1204R of the following pumps: Rule 800 (20DA, 20DA-24)
Rule 1100 (27DA, 27DA-24)
Rule Automatic 800 (20SA, 20SA-24)
Rule Automatic 1100 (27SA, 27SA-24)
Rule LP900D, LP900S
Rule mate 800 (800B, 800B-24)