Details: * . * Spiral fluted with unique structure, slightly can open different aperture specifications. * No need to use the punch center, compared with the ordinary drill bit, it is not easy to be broken. * Deburring, chamfering, elliptical magnification, their function was not able to, but it is possible. * Tool Application: Drilling Machine, Bench Drill. Work while water cooling, can effectively extend the service life of the drill bit, 250-400 RPM drilling speed is recommended. * Cutting material: cast iron board, aluminum, wood, insulation boards, pvc board thickness within 5mm. Use the drill bit to make different stitches * Color: Gold (as pictures show) * Material: HSS * Surface: Titanium Coated * Standard: 4-22mm (4, 6, 8, 10, 12, 14, 16, 18, 20, 22mm) Package Content: 1 * Step Drill Note: 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.