Industrial grade cobalt steel. 135o split point for quick start and no walk application. Cobalt for much higher hot hardness and abrasion resistance. Ideal for drilling in steel, stainless steel, heat resistant steel, cast steel, sintered metal, and super alloys. Dia.1.0-13mm If you need any further information about the Drill bits set, please contact us, and we can send you more pictures of our Drill bits set with good price. We believe we can serve you in a positive manner.