1.Material: Zinc alloy 2.Surface finished:BP,CP,NP,SCP,SNP,GP,AB,AC 3.OEM is available Zinc alloy security door chain 1)Material: Zinc alloy2)Surface finished:BP,CP,NP,SCP,SNP,GP,AB,AC.4)OEM is welcome Advantage Of hinge: 1)Good quality with best price.2)Self-manufactured and direct selling.3)High reputation, good credit standing and on time delivery.4) Have a good after service