State of the art 2 disc dry clutch engineered for Yamaha KT100S engine in Jr or Sr Sportsman classes. Use with 3 hole and 4 hole Can muffler or the new style spec sportsman pipes. Comes with bolt-on sprocket. Steel drum features new longer lasting steel alloy for 2010. Optional lightweight aluminum drum now available. Small size just 2 1/2" disc for low inertia.