... C51900,C60600,C17200,etcAlumimum100,5052,6061,6063,etcAbility for the surface finish: ElectroplateZinc plated(while,colour,dacroment),Nickel plated ... coating,etcPolishingGrinding and polishing,etc,except mirror finishAbility for the tolerance: Roundess0.002mmCylindricity 0.003mmRoughness Ra0.32Straightness0.01/200mmHow ... for exporting so that you couldavoid lots of risks. non-standard hex nut