MATERIAL & SIZES: Universal 50pcs HSS mini twist drill bit set, high speed steel with titanium coating, containing 5 sizes: 1mm/1.5mm/2mm/2.5mm/3mm with drilling capability for wood, plastic, aluminum, copper.Good toughness of HSS twist drill: wear resistance, drilling ability. Suitable for use on a variety of materials including alloy steel, iron, non-alloy steel, copper, bronze, cast iron, hard plastics and plexiglass.Titanium High Speed Steel: Classic high speed steel with titanium coating for proven capability. In the drilling work has excellent processing performance, all the sharp ligaments are sticky and smooth, without burrs.Titanium Lens: Our candy fouse titanium coated drill bit improves the surface hardness of the drill to improve the machining precision and improve the surface quality of the drill to reduce the coefficient of friction with the processing of the work piece , titanium and improve temperature resistance and wear resistance, thereby increasing the processing speed for high-speed processing