... .8,8.8,9.8... Double End Bolt,Special Head Bolt,Bolt Maker ,M6 Bolt Dimensions1.What’ ... at modern concept of management.3. We have special research person and more than 100 equipment to ... tighten the fasteners by wrench ,key ,bit and spanner.When head become thicker,and then the socket ... had strong technology support,a special quality control procedure,have some special persons in charge of quality ...