chain sprocket 1,25b-120b all type 2,high precision cnc tech 3,black oxide ... machinery, metallurgy, mine, build, electron, port etc..professional automation production and conveying transmission equipment MaterialC45, A3, 40Cr, 20CrMnTi, 42CrMo, copper, ... stainless steel and so on as per your requestprocessForged or castingHeat treatmentHigh frequency ...