Specifications: The ladder of its unique structure, a bit can open a variety of specifications of aperture. Do not need to use center punch, compared with the ordinary twist drill is not easy to be broken. Deburring, chamfering, elliptic hole enlargement, twist drill, the function of them was unable, but it is possible. The use of tools: drill, bench drill. Work while water cooling, can effectively extend the service life of drill bit, recommend drilling rate of 250-250 RPM. Cutting material: sheet iron plate, aluminum, wood, insulation boards, PVC plate thickness within 5mm. Use a drill to make a variety of eyelets. Type: Drill Bit Color: Golden Material: HSS 4241 Surface Finishing: Titanizing Features: Cone Design, Useful Tool, 4-22mm Cutter Standard: 4-22 mm (4, 6, 8, 10, 12, 14, 16, 18, 20, 22mm) Notes: Due to the light and screen setting difference, the items color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x Drill Bit