1.Material:aluminum,brass.cooper. carbon steel 2.Surface:zinc plating ,powdered 3,Great quantity get lowest price Compression Spring, 1.Material:steel,stainless steel.brass,aluminum,brass.cooper. carbon steel. 2.Surface:zinc plating ,powdered,pas 3.All our products are made by high-quality steels and first-class producing process Our Advantage; 1 FactoryEstablished in 2000,got SO 9001-2004 ...