Industrial-duty clutch mated to high-performance Cat Pump increases durability and dependability. Convenient remote control of on-off function optimizes system performance. Superior strength forged rotor, hub and armature offer superior flux and maximum torque for long life. Single groove 7 pulley, "A" type belt and 20mm shaft. Fits Cat Pumps models 323 and 390 piston pumps and 310-350, 310B-350B, 310S-350S, 311-351 and 317-357 plunger pumps.