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 ... is SS201,202,302,304,316...copper is shiny brass , pure copper,such as H62,H65,H68...Aluminum is good Aluminum ...