? TiAIN Coating? Each drill bit surface of this cobalt drill bit set is coated with TiAIN coating. Compared to ordinary drill bits, it can achieve faster cutting speed and also cut harder materials. The service life of drill bits can also be extended by nearly 5 times??? Multifacet Tip Design? HSS M35 cobalt drill bit set for hardened steel has a special design of multifacet tip at the head, which greatly improves the drilling efficiency compared to ordinary drill bits. It is suitable for hardened steel with excellent cutting performance??? Various Sizes? 29 sets of drill bits include 1/16″, 5/64″, 3/32″, 7/64″, 1/8″, 9/64″, 5/32″, 11/64″, 3/16″, 13/64″, 7/32″, 15/64″, 1/4″, 17/64″, 9/32″, 19/64″, 5/16″, 21/64″, 11/32″, 23/64″, 3/8″, 25/64″, 13/32″, 27/64″, 7/16, 29/64, 15/32″, 31/64″, 1/2, can meet more needs like Hardened Metal, Stainless Steel, Cast Iron and other soft materials??? M35 Cobalt Drill Bit? The M35 cobalt drill bit is a durable, sharp and robust drill bit suitable for cutting stainless steel, iron castings, copper, aluminum and other soft metals as well as plastics, wood etc??? Easy Storage? The drill set includes drill holders with size indexes and is packaged in a small, strong metal box package for easy storage and sorting. If you have any questions, please refer to us and we will be happy to help you.