46T/47T/48T/49T/50T/51T/52T/53T/54T/55T/56T. etc Front sprocket: 13T/14T/15T/16T/17T. etc 415.420.428.428H.520 etc Raw-materials C45, A3 etc Heat treatment High frequency heat-treatment, Carburizing heat-treatment, etc Surface treatment Sand blasting,...