1.Mateial: Carbon Steel , SS, Alumi-num,etc 2.Finish:zinc/nickel plated 3.RoHS-approved 4.Package:poly bag screw-nut columns ... ,copper,carbon steel,aluminum3. surface treatment: white zinc,color zinc,blue zinc,yellow zinc,black zinc,chorme plated,nickel plated,black oxide4.Thread sizes: all kinds of British ...