It is applicable to 420 Chain Master Link / Countershaft width 17mm . The method to distinguish 420 and 428 sprockets is to measure their thickness Material: 45# Steel，Has high strength and deformation resistance. Maybe you re hearing squeaking sounds from your chain while youre riding at low speeds . Maybe you're feeling vibrations or hearing clicking soundwhen you roll your bike forward or while coasting to a stop . In any case , you' ll want to check your front sprocketWhen this particular part starts to malfunction , it's always a good idea to replace it right away . 420 Chain sprocket Fits Various Sports Vehicles: Designed to fit 50cc 70cc 90cc 110cc 125cc dirt bikes, mini, bikes, ATVs, and 4-wheel go karts.420 Go kart sprocket 17mm < br >< br >Please check the details of # 420 Roller Chain Specifications in the picture to confirm the product's compatibility. < br >< br >< br > < br >Package quantity: < br >1）420H Link head*1 < br >3）Gasket*2 < br >5）Sprocket * 1 < br >=4 Pieces