... years experience in fastener feild Name: Red copper coupling ;Copper coupling ; Coupling red copper Ability for the material of this kind of ... coupling: Grade3.6,4.6,4.8,5 ... surface finish: ElectroplateZinc plated(while,colour,dacroment),Nickel plated,copper plated,gold plated,chrome(3+Rohs &6+ ) ... that you couldavoid lots of risks. Red copper coupling