... in fastener feild Name: Red copper coupling ;Copper coupling ; Coupling red copper Ability for the material of this kind of ... 6061,6063,etcAbility for the surface finish: ElectroplateZinc plated(while,colour,dacroment),Nickel plated,copper plated,gold plated ... coating,etcPolishingGrinding and polishing,etc,except mirror finishAbility for the tolerance: Roundess0.002mmCylindricity 0.003mmRoughness Ra0. ...