Set includes model No. 48899100 13-hole bit and model No. 48899105 9-hole bit. High speed steel makeup is ideal for cutting into stainless steel, aluminum, brass, copper, plastic, and more. 2 cutting edges provides true round holes every time. Black oxide finish resists corrosion for longer life. Speed start tip starts fast and reduces the risk of bit walking. Laser etched markings for fast, easy hole size identification. 3-flat shank prevents bit from slipping in the chuck.