... ,8.8,10.9,12.9Surface:black zinc,parkerising,chrom plated and oxide coatingCertificate:ISO9001:2000The products have good after-sale ... : SCM435,10B21Surface FinishZn- Plated,Ni-plated,Passivated,Tin-plated,Sandblast and Anodize,Chromate,Polish,Electro Painting,Black Anodize,Plain,Chrome plated Normal DiaM4-M30Heat TreatmentTempering ...