Dremel 1/8" Diameter Tungsten Carbide Cutter is used for shaping, smoothing and material removal. It is made of tungsten carbide, which is the next hardest material to diamonds, making it extremely durable and long-lasting. This cutter can be used on a variety of materials including hardened steel, stainless steel, cast iron, non ferrous metals, fired ceramics, plastics, hardwoods and other hard materials. It is important to note that this cutter should not be run in excess of 35,000 RPM.