drill bit is a 135-degree split-point, heavy-duty, round shank drill bit made of high-speed steel and cobalt with a gold oxide finish. For best use drill with hardened, tempered alloy steel, stainless steel, nodular graphite, malleable cast iron, titanium, nickel and hard material-cemets. It is suitable for drilling to a depth up to two-and-a-half times the diameter of the drill. The shank diameter is the same as the drill size.