Double End Bolt,Special 1.ISO,ANSI,CE,JIS,DIN,BS& non- ... 3.Grade:4.8 ,6.8,8.8,9.8... Double End Bolt,Special Head Bolt,Bolt Maker ,M6 Bolt Dimensions1.What ... not break when you tighten the fasteners by wrench ,key ,bit and spanner.When head become thicker,and then the socket ... manufacturers,it is convenient to tighten the fasteners by wrench,,bit,key etc.3.The scrows are also much deeper than ...