Pentair 355188 Diffuser Replacement Challenger High Pressure Inground Pump Diffuser replacement Fits Pentair Challenger high pressure inground pump models CHII-NI-3/4F, CHII-NI-1F, CHII-NI-1A, CHII-NI-1-1/2A Measures 15-inch length by 15-inch height by 7-1/2-inch width