This is a replacement Clutch Nut for Hot Bodies 1/8 scale vehicles. This nut threads onto the end of the crank shaft. It will hold the fly wheel to the crank shaft. This part is intended for use with the three shoe clutch. This will allow the engine to transfer power from the crank shaft to the flywheel. Recommend using part # C8083 Three shoe clutch fly wheel, part # C8044 Clutch Springs, and part # C8043 or C8043-1 Clutch Shoes.