【M35 Cobalt, TiAlN Coated drill bit Set】Includes 21 pc, 16 sizes: 1/16"(2pc), 5/64"(2pc), 3/32"(2pc), 7/64"(2pc), 1/8"(2pc), 9/64", 5/32", 11/64", 3/16", 13/64", 7/32", 15/64", 1/4", 5/16", 3/8", 1/2". 【Durable M35 (5% Cobalt) Material】Enhanced wear resistance, good toughness and hardness, superior hot hardness (red hardness). Improve cutting performance at high speeds. 【Self Drilling Pilot Tip】Compared to standard drill tip, more effortless, convenient. No need to ensure accuracy by pre-drilling a pilot hole. 【Titanium Aluminum Nitride‌ Coating】Provide advanced heat resistance, wear resistance and long life. Guarantee excellent results across different working conditions. 【Wide Application and Easy Operation】Ideal for hard materials: stainless steel, steel and cast iron as well as wood, aluminum alloys and other metal. Not suitable for glass or ceramic material.