4001-13T 1" 40 Pitch 13 Tooth Clutch Sprocket.

Fits 1" Eco, Crush, Gator, Bully style clutches. EC Carburetors designed this 1" #40 Clutch driver to meet the demands of racing lawnmower racers that want all the performance of a 1" 4-Disc Clutch with the strength of the #40 chain commonly used in lawnmower racing. The #40 pitch chain is also common on many mini bikes and some recreational go-karts.