Drill America High Speed Steel Annular Cutters are designed for fast, efficient hole making and cut only that material necessary to produce a quality hole. High-speed steel tools are good for most general purpose applications, offering a combination of hardness and toughness for wear resistance. Sometimes called mag drills or magnetic drill bits, Drill America Annular cutters have a 3/4" Weldon Shank for use with magnetic drill press only. Do not use this cutter with a standard hand drill or drill press.