... 1,ANSI,DIN type 2,high precision cnc tech 3,black oxide anti-corrosion 4,large production, large stock Sprocket 1 ... . high precision and good wear resistance. 2, surface treatment is black, galvanization, chroming and colored drawing. 3, material is A3\C45 ... plastic bag and outer carton box or customer requirement. ANSI machine black oxide sprocket/hard teeth drive sprocket