Features 1、The aperture scale is clear, and it should be smaller than the ordinary twist drill. It can open a beautiful aperture without using a center punch. 2、Deburring, chamfering, rounding and reaming, functions that can not be done with twist drills can also be completed. 3、Ladder structure, widely used, a drill can open a variety of sizes and apertures 4、Suitable for workpieces with hardness below 25° such as iron plate, aluminum plate, PV plate and insulation plate 5、Using high-quality materials, strong and durable, has a long service life Specification Item Type: Step Drill Set Material: High-speed steel 4241 (Ti coating) Series: Inch Step Drill Specification: 1/4-1-3/8, 3/16-7/8, 3/16-1/2, 1/8-1/2, 1/4-3/4 (Unit: Inch) 5pcs set Applicable Places: Suitable for workpieces with hardness below 25° such as iron plates, aluminum plates, PV plates, and insulating plates. Package List 5 x Step Drill