... 4.8 ,6.8,8.8,9.8.... Copper Bolts,Copper Bolt,Brass Bolts.1.What’s the specification ... our Products ? MaterialsCarbon steel,Stainless steel,Alloy steel,Copper,Aluminum are available.Carton steel is high quality iron ... steel is SS201,202,302,304,316...copper is shiny brass , pure copper,such as H62,H65,H68...Aluminum ... The material are always use C1022 ,The percent of C element is 0.18%-0.23% ,is higher ...