... special fastener field 1,Name: Black thread bolt;Thread bolt;Black bolt 2,For the similar bolt,what can we do ?(1), Ability for ... the material of this kind of bolt: Grade3.6,4.6,4.8,5.6,6.8 ... the surface finish: ElectroplateZinc plated(while,colour,dacroment),Nickel plated,copper plated,gold plated,chrome(3+Rohs &6+ ) plated,anodic oxidation ...