... electroplate balls. zinc-plated, nickle- plated, chrom-plated, copper cover Model Number2mm-50mmApplicationtoy, anit-rust purposeShapeshperialMaterialsteelDimensions2mm-50mmChemical CompositionsteelCertificationISO9001Copper ... machines, hardware, bearings, wheel, bicyclesand trust bearing pulleys Copper Plated Ball/zinc-plated, nickle- plated, chrom-plated, copper covered ball Copper Plated Ball,