Double End Bolt,Special 1.ISO,ANSI,CE,JIS,DIN,BS ... 4.8 ,6.8,8.8,9.8... Double End Bolt,Special Head Bolt,Bolt Maker ,M6 Bolt Dimensions1. ... Plated,chromium plated,Tin plated,Black phosphating ,anodized ,Parkerising,and Environmental Plated is used in our products,Hexavalent chromium ... tighten the fasteners by wrench ,key ,bit and spanner.When head become thicker,and then the socket is much deeper than ...