... 3.Grade:4.8 ,6.8,8.8,9.8... Double End Bolt,Special Head Bolt,Bolt Maker ,M6 Bolt Dimensions1.What ... Plated,chromium plated,Tin plated,Black phosphating ,anodized ,Parkerising,and Environmental Plated is used in our products,Hexavalent chromium are ... of the quality control6. Certificate:Provide dimensions report,chemical report and other testing report .Good service We can manufacture nonstandard ...