... .Grade:4.8 ,6.8,8.8,9.8.... Copper Bolts,Copper Bolt,Brass Bolts.1.What’s the specification of our Products ... ? MaterialsCarbon steel,Stainless steel,Alloy steel,Copper,Aluminum are available.Carton ... ,10B38...Stainless steel is SS201,202,302,304,316...copper is shiny brass , pure copper,such as H62,H65,H68...Aluminum is good ...