... ss304,ss316,40Cr,etc 3.SGS,ISO 4.black,zinc plated,HDG,etc double threaded bolts 1.Features Material: Carbon ... steel, stainless steelFinished: PL, Zinc plated, HDG, Dacromet zinc, Black oxide, Nickel plated, Chrome plated, Cr+3, Brass plated Grade: 4.8-8.8 Standard ... .8,6.8,8.8,12.9ColorPlain, blue plated, white plated, yellow plated.StandardISO,GB,DIN,JIS,ANSICetificateISO9001-2008,SGS,ROHS Function ...