These double flute cutters are made of solid tungsten, clockwise cutting. The fishtail profile ensures cutting to the centre, allowing boring too. Usable on cast iron, hardened cast iron, steel, cast steel, brass, aluminium, and even glass, plastics and carbon fibre. One each of shaft diameter 1.0 - 2.0 and 3.0 mm. For use with the Micro Mill (#980103).