General description Center Drill Bit Kit includes 5 pieces of center drills with varying diameters, designed for precise center drilling in wood and metal materials. Technical specifications Sizes: Diameter of 1.5 mm, 2 mm, 2.5 mm, 3 mm, and 4 mm Material: High-speed steel Usage Ideal for machining center holes on the end faces of shafts and other components Suitable for processing materials such as iron, steel, copper, and aluminum