... 6.8,8.8,9.8..... Hollow Bolt,Stainless Steel Hollow Bolt,Bolt with Internal Thread.1.What’s the specification of ... is SS201,202,302,304,316...copper is shiny brass , pure copper,such as H62,H65,H68...Aluminum ... ,washer,rivet, stud, pin,wrench and so on .2.Our company had good reputation with customers from American,Europe ... any time !Tel:+86-15917002605 Stainless Steel Hollow Bolt With Internal Thread