The Heller hole saw set includes a total of nine pieces and is specifically designed for professional applications. It offers a variety of hole saws with a diameter of 51 millimeters, made from high-quality HSS bi-metal. This choice of material ensures high durability and efficiency when cutting through various materials. The set also includes a centering drill with a diameter of 6.35 millimeters, which allows for precise positioning and clean drilling. The hole saws are ideal for use in metalworking and provide reliable results that meet the demands of professionals. With this set, users can create precise and clean holes in different materials, making it an essential tool for craft projects and industrial applications.