Features Made of hardened heat treated steel, very durable to use They can provide the perfect cut every time, suitable for high speed drill bit High quality HSS drill bits have reliable performance and durability when drill holes on plastics, Aluminum/copper with a thickness of 1mm and many other types of materials There are 8 different sizes, and comes with a hard wooden packing case, ensure deposit safely and take easily Suitable for carpenter, builder, electrician, workshop, DIY, domestic crafts, amateurs, stylist,etc. Description: This HSS drill bit set is specially designed for professionals, it suits DIY fans' tool kit as well. These drills are made of hardened heat treated steel, so they are very durable to use. Features: 1. Made of hardened heat treated steel, very durable to use. 2. They can provide the perfect cut every time, suitable for high speed drill bit. 3. High quality HSS drill bits have reliable performance and durability when drill holes on plastics, Aluminum/copper with a thickness of 1mm and many other types of materials 4. There are 8 different sizes, and comes with a hard wooden packing case, ensure deposit safely and take easily. 5. Suitable for carpenter, builder, electrician, workshop, DIY, domestic crafts, amateurs, stylist,etc. 6. Fit into power tools chuck securely and eliminates slip.  Specifications: Material: HSS Shank Diameter: 1/2inch Shank Type: TriangleSurface Treatment: Polishing & Nitrogenization Size: 14mm, 16mm, 18mm, 19mm, 21mm, 22mm, 24mm, 25mm Weight: Approx. 1788g Length: Approx. 150mm / 6inch Package Include: 1 Set x Twist Drill Bit  Package List