Comet 400 Series Clutch - 11 Teeth - 5/8in. Bore 209748 Single Sprocket Self Contained 400 Series clutches have more contact surface than most competitors and built-in staying power Almost 3 3/4in. squared of steel friction material engagement shoe surface assures positive pulling power as long as the RPM is in full contact range There is no slipping when you need the go-power