05-06 ZX6R 636 Vortex 520 14/45T Steel Sprocket & RK GB520XSO Chain Kit (CRK6353) Front Sprocket - 14T and Rear Sprocket - 45T Electroplated satin black for corrosion resistance. Teeth are hardened for increased durability. Suitable for both street and race use Made of the highest quality steel.