Proxxon 2 Piece Tungsten Carbide Milling Bit Set Supplied as a pack of two, with one of each in the pack. A cylindrical bit 2.3mm diameter by 5.0mm long and a 2.3mm diameter ball end bit. Made of wear resistant highly compressed fine granular tungsten. Used for vibration-free milling of high accuracy dimensions. It is advisable to secure workpieces well. For milling steel,cast steel, non-ferrous metals, plastics and extremely hard materials. May be used for technical work, for engraving and milling of PC cards. Shank diameter 2.35mm