Faithfull Metric HSS Drill Bits are quality roll forged flute twist drills with a black oxide coating, manufactured from HSS in accordance with DIN338 standard. Suitable for use in alloy steels, carbon steels and hardened alloy steel. A cutting lubricant is recommended. Although designed for cutting metal, they are also suitable for drilling holes in plastic, timber, chipboard and plywood. Supplied in a robust plastic case that secures and protects the drills. The contents can easily be viewed through the flip action transparent lid.