Coupling Fasteners,Connecting 1.ISO,ANSI,CE,DIN,BS& non-standard ... is capable 3.Grade:4.8 ,6.8,8.8..... Coupling Fasteners,Connecting Fasteners,Aluminum Fasteners. 1.What’s the specification ... steel,Copper,Aluminum are available.Carton steel is high quality iron,such as 1022,1018,1010,1008,1015...Medium carbon steel ...