High-speed steel: suitable for workpieces less than 25 mm in hardness, such as carbon steel, sheet metal, insulation boards, PVC panels, boards and wood with a thickness less than 5 mm. Made of heat treated forged high speed steel (HSS) with titanium nitride coating for longer life. Good Design - Triangular shank holds power tool chuck securely and eliminates slippage. The two flute design removes chips faster and allows particles to escape easily. You can use water to cool it down when it works and it can be used even longer. A Necessity for the Family, DIYers or Professionals - Perfect for home repairs and light duty jobs such as drilling holes in plastic, aluminum, copper and many other types of sheet metal . 10-45mm Nitride Step Drill Bit Set with HSS Hex Shank for Carbon Steel, Sheet Metal, Insulation Boards, PVC Boards, Boards Features: 1. High speed steel for longer life. 2. The triangular shank prevents slipping in the chuck. 3. The double blade design allows for faster and smoother cutting. 4. The advanced double spiral flute design outperforms the straight flute design and extends the life of the mouthpiece. The split tip increases speed, and it also includes laser-etched measurements to increase footstep visibility. 5. The sharp edge guarantees easy cutting through most sheet metal, plastic and other materials. Features: Material: high speed steel. Size: 10-45mm (8 levels: 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm). Content: 1 drill.