... steel 35#,stainless steel, brass,aluminum4.Surface of eccentric screw : Black, Zinc Cr+3, Yellow Zinc Cr+6,H.D.G ... ,Passivated,Tin-plated,Sandblast and Anodize,Chromate, Polish,Electro Painting,Black Anodize,Plain,Chrome plated,Hot Deep Galvanize(H. D. G ... request of 100%,and have 18 month warranty. screws for cement board