Diameter: 3.5mm. Suitable for general purpose applications, including: copper, iron, magnesium, mild steel, wood, plastic. TiN coated high speed steel, roll forged with 118° point. DIN 338. Part of a range of HSS TiN coated drill bits in metric sizes from 1.0mm - 13.0mm (Part Nos. 32965 - 32992).