Ultimate Racing screws are made of 12.9 steel, which is the best grade you can use on your RC model. The Ultimate Racing Premium Screws have a chromed finish to give superior protection against corrosion. Ultimate Racing Premium Screws are far superior to the screws that come stock with your RC kit, so these are a great upgrade for your car, truck or helicopter! Never worry about stripped heads or damaged screws again. You will not find a better screw for your RC model at this quality-price rate.