HSS and Titanium Coating - High speed steel makes it more durable than others, titanium coating makes it easy to cut steel plate, aluminum sheet, copper, plastic, metal wood and many other types of sheet metal with ease. It can automatically deburr holes while drilling to keep the bit clean. Slit tip increases speed.< /p> A necessity for the family, DIYer or professionals - Perfect for home repairs and light duty jobs such as drilling holes in plastic, aluminum, copper and many more types of sheet metal. Package include: 1 HSS step drill 6-60mm (12 steps: 6mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm) The step drill bits are made of high speed steel with a titanium coating, which allows for a long service life. < p>Features: 1. High speed steel for longer life. 2. The design of double cutting blades allows faster and smoother cutting. 3. Advanced double spiral flute design outperforms straight flute design and extends bit life. The split tip increases speed, and it also includes laser-etched measurements to increase footstep visibility. 4. Sharpness easily cuts most sheet metal, plastic and other materials. Features: Material: High Speed Steel. Drill Sizes Stepped: 12 steps (6mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm).< /p> Contents: 1 drill bit from 6 to 60 mm.