... 4) OEM offered 5) We are a factory with 16-year history 16-year history, professional sprocket ... sprocket2Thickness:6-7.0mm3Hardness:40-50HRC4Factory supply directly5Sprocket with A3,45#steelSpecificationsFront:12T/13T/14T/15T/16T ... CarburizationSurface treatmentSand blasting, Dull polish, Galvanization, Chrome plating, Painting,PackagingBlister card, Slide blister, Plastic bags, Carton, Vacuum ...