Countershaft Sprocket - 16 Tooth - Yamaha Made from SCM-435 carbon- steel and impregnated to zero breaking risk and extended sprocket life, Ultra-hard surface layer (.5 mm) reduces friction to prevent power loss caused by chain drag, Fully lightened with radial holes for off-road and street applications, Grooved teeth for off-road applications, just like our factory racing parts, allowing fast dirt removal, Factory Team specification parts from the company supplying factory teams