Features:* Ladder with unique structure, slightly can open up different aperture specifications.* No need to use central punch, compared with ordinary twist drill is not easy to break.* Deburring, chamfering, elliptical magnification, twist drill, their function was not able to, but it is possible.* Tool application: drill, bench drill. Work while cooling with water, can effectively extend the service life of the drill bit, we recommend drilling speed of 250-250 rpm. Specifications:Product Name: Step Drill Material: HSS (High Speed Steel) Color: Gold Shank: Hex Shank Diameter: 6mm Shank Length: 30mm Total Length: 110mm Size: 6-35mm(6-8-10-12-16-18-20-22-25-28-30-32-35mm) 13 Step Suitable for: carbon steel plate, thin iron, insulation board, pvc board, wood board, and the thickness of the plate is less than 5mm drilling Quantity: 1Pc Package Content: 1 × Step Drill Note:1. Transition: 1cm=10mm=0.39 inch.2. The actual colors of the item may be slightly different from the pictures shown on website caused by many factors such as brightness of your monitor and light brightness.3. Please allow slight manual measurement deviation for the data.