Pentair 073128 Impeller Replacement WhisperFlo 1000 Series Inground Pool and Spa Pump Impeller replacement Fits Pentair WhisperFlo 1000 Series inground pump models WFE-4, WFE-26, WF-4, WF-26, WFK-4, WFDS-4, WFDS-26 Measures 5-inch length by 2-1/4-inch height by 5-inch width