Crafted for exceptional cleaning and finishing, these knot end brushes by United Abrasives excel in reaching recessed areas and pipes, making them an essential tool for intricate metalwork. With a diameter of 1 inch and a wire size of .020 inches, they are designed to operate at a maximum speed of 22,000 RPM when used with portable power tools like die grinders. The crimped wire configuration offers high flexibility, while the knot wire style ensures aggressive cutting action, making these brushes ideal for tackling ferrous metals such as iron and steel, as well as rust and welds. Whether you're engaged in detailed surface finishing or general cleaning, the circular flared shape provides a superb side cleaning action, ensuring that even the most troublesome spots are thoroughly addressed.