The Firepower 1423-2113 Standard Twist Carbon and Stainless Steel Wire Wheel Brush has a 4-inch diameter, 0.020 wire size, a 5/8"-11 NC arbor hole and a maximum RPM of 12,500. Firepower wire wheel brushes are designed for tough jobs. Each individual knot contains an equal number of top quality high carbon tempered wires, which gives the wheel an exact balance and long life. Firepower brushes are well-suited for use in the welding and fabricating industries. They are used for surface preparation prior to welding and brazing and for removing weld scale and spatter after the welding operation.