Silicon bronze fasteners are excellent for use in many marine and commercial applications which was made from copper with silicon added for strength.Silicon bronze is known as a high-strength alloy,having a several important factors including high conductivity,excellent corrosion resistant to sea water,gases,sewage and atmospheric conditions. Our silicon bronze wood screw(C65100,C65500 alloy material was purchased from ISO certificated source) was made to ANSI,DIN,BS,etc. Length: 6mm-150mm Diameter: #4 - #24 Head style:Flat,Oval,Round,hexagon,etc. Packing:polybag and carton Output:60 tons per month. Sending sample free of charge.