17mm Engine Sprocket Retainer Plate Sets for 50cc 70cc 90cc 110cc 125cc ATV Dirt Bike Go Kart Pit Bike Dune Buggy Quad 17mm Engine Sprocket Retainer Plate Sets fits for 50cc-125cc ATV,Dirt Bike,Go Kart The set cantain:an engine sprocket plate,two sprocket plate fixed screws The inside diameter:17mm