Turbine drive transmission for the last group of Spin Scrub 50 carpet cleaners. Has the LARGE 6 corner drive pin receiver (as shown in picture.) Has the 2 supply line ports. The last models produced include F5915905 & F5914901. Often a bearing inside will lock up or the air driven fan will crack and break. Only sold as full part complete. older units have a small square drive look up (H-43191021) 11/22/21 dda