... years experience in fastener feild Name: Red copper coupling with gap; Red copper coupling ; Coupling with gap Ability for the material of this kind of coupling: Grade3.6,4.6,4. ... the surface finish: ElectroplateZinc plated(while,colour,dacroment),Nickel plated,copper plated,gold plated,chrome(3+Rohs &6+ ) plated,anodic ... for exporting so that you couldavoid lots of risks. Red copper coupling with gap