Unibor 25118 Diameter Annular Cutter, Bright Finish, 9/16-Inch, 1-Pack 9/16-Inch Diameter x 1-Inch depth of cut M35 cobalt cutter with up to 30-Percent longer life Standard 3/4-Inch shank with 2 flats at 90-Degree to fit most magnetic drills Unique geometry provides faster feeds, less friction and a smooth hole finish in various materials - Mild steel, Hi Tensile steel, Stainless Steel, Brass, Aluminum Use coolant or lubrication