... ,chromium plated,Tin plated,Black phosphating ,anodized ,Parkerising,and Environmental Plated is used in our products,Hexavalent chromium ... the fasteners by wrench ,key ,bit and spanner.When head become thicker,and then the socket is much deeper than some ... the quality control6. Certificate:Provide dimensions report,chemical report and other testing report .Good service We can manufacture nonstandard ...