This is a professional 28 pcs drill bit set. It includes drill bits with tip diameters of 0.5mm, 0.8mm, 1.2mm 2mm. Industrial grade high-speed steel for higher durability and sturdiness. Suitable for drilling in tough material, including aluminium, cast iron, brass, copper, magnesium alloy, plastics, etc. Feature - Color: Silver - Material: High Steel - Bit diameter: 0.5mm, 0.8mm, 1.2mm, 2mm. - High-speed steel with coating treatment, tougher and more abrasion resistant for longer working life and high work efficiency. - Round design drill bits, accurate and fine, increase drilling speed. - Mainly for drilling wood, plastic, fiberglass, printed circuit board, and metal including copper, aluminum, tool steel, cast iron, and heavy-duty abrasive alloy metal, etc. - for home DIY, building and engineering use etc.