& OOTDTY Features: Unique ladder design, can open multiple aperture. Maybe deburr, chamfer and open hole, but a regular twist drill can't. Little rock, can carve a nice aperture without first using the middle stamp. Water for cooling during operation, can effectively prolong the service life. Deburring, chamfering, elliptical magnification, twist drills, drills, bench drills. Widely used for cutting holes in various materials, such as steel, wood, thin iron, aluminum alloy, insulation boards, pvc sheet, etc. Recommended drilling speed 250-400 rpm. Suit to be used in hardness below 25° artifacts, plate thickness below 5mm. Step drill bit only, other accessories demonstration in the picture are not included. Specifications:Material: HSSMeage: Application. app.10.6x1cm/4.17x0.39in Style: 4-52mm(4,8,12,16,20,24,28,32,36,40,44,48,52mm)Color: GoldQuantity: 1 Pc Note:No retail package. Please allow 0-1cm error due to manual measurement. Pls make sure you don't mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package Included:1 x Step Drill Bit