A. This engine part is designed specifically for motorcycles, with the model number 420. Its design aim is to provide more stable and efficient power transmission for motorcycles. B. This part comes in a variety of specifications, including screw parts and sprockets with different numbers of teeth. For example, there are 420 - 10T (large hole), 420 - 11T (large hole), 420 - 12T (large hole), 420 - 13T (large hole), 420 - 14T (large hole), 420 - 15T (large hole), 420 - 16T (large hole), 420 - 17T (large hole), 420 - 18T (large hole), 420 - 19T (large hole), etc., which can meet the diverse needs of different users. C. Whether it is for daily riding or special scenarios such as off - road riding, with its excellent design and compatibility, this part can bring good performance to the motorcycle and help make the riding smoother.