Special Fasteners Nuts Bolts 1.ISO,ANSI,CE,DIN,BS& non-standard fastener ... :4.8 ,6.8,8.8.... special nuts bolts screw fasteners Special Fasteners,Special Nuts Bolts Screws Fasteners,Specail Screws Fasteners . 1 ... steel is SS201,202,302,304,316...copper is shiny brass , pure copper,such as H62,H65,H68...Aluminum is good ...