Abrasive burrs, also known as rotary files, are used for stock removal, deburring, shaping, and smoothing. Burrs are usually made of tungsten carbide, but can also be of high speed steel (HSS). Steel burrs are stronger, but carbide allows for a sharper tool. Burrs are available with various head shapes, such as oval, cone, ball, or cylindrical. The design and arrangement of the teeth on the head determines cut type. Single cut, also called standard, has one row of parallel diagonal teeth to remove large quantities of material but can leave a rougher finish. Double cut has two cutting edges that cross like an X and are capable of working with harder materials. Diamond cut burrs leave a finer finish and are effective for heat-treated and alloy steels.