Name:Step Drill Bit Type:Gun Drill Bit, Step Drill Bit Material:High Speed Steel 4241 (suitable for use in hardness under 25 ° artifacts, such as Iron plate, aluminum board, PV panel, insulation board) Size:4-12mm,4-20mm,4-32mm Working Length (mm):32mm Finish:Black Oxide, ZINC, Plain Style:Luxury...