This is a diaphragm service replacement for the following products: RADIUM MPR (multi-pump regulator)RADIUM MPR-RA (multi-pump regulator)RADIUM FST-R (fuel surge tank regulator)RADIUM FSTR-RA (fuel surge tank regulator)RADIUM DMR (direct mount regulator)RADIUM DMR-RA (direct mount regulator)RADIUM FPR-D (fuel pressure regulator damper)RADIUM FPRD-RA (fuel pressure regulator damper)RADIUM PUMP HANGERS with built-in FP Rs (all)