[ 12 STEPS ] Includes 3/16, 1/4, 5/16, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4, 13/16 and 7/8 inch sizes allowing you to drill up to 12 holes with different diameters. [ M2 HSS STEEL ] Made from M2 High Speed Steel (HSS) for strength, durability, long life and accurate and precise drilling. M2 HSS steel's resistance to high temperatures minimizes the risk of overheating during drilling, promoting consistent performance. [ STRAIGHT FLUTE ] Equipped with a straight flute and X-type opening to minimize friction during drilling, enhance chip evacuation by channelling debris away from the drilling area, provide added stability, process deeper holes and promote faster drilling speeds. 3/8 inch 3-sided shank for easy operation. [ HEAVY DUTY ] Industrial nitrided coating to improve hardness, wear and corrosion resistance as well as reducing surface damage with clear and distinct sizing laser markings for high visibility. [ IDEAL FOR ] Drilling and enlarging holes, chamfering, deburring, 5mm iron sheets and aluminum sheets.