Cup brushes are for use on portable power tools for addressing larger surface areas more efficiently than a wheel brush. Cup brushes featuring a threaded nut are designed for smooth, efficient operation on angle grinders to make quick work of large jobs. Utility cup brushes featuring a permanently attached 1/4 in. stem are more suitable for smaller jobs and are recommended for use on high-speed air tools for the most effective brushing action and longest life. Cup brushes are manufactured with individual knot hole and solid ring construction for high performance and long life.