Max speed: 20,000 RPM. Constructed of hundreds of resin bonded cloth abrasive sheets firmly attached to a balanced core. During use, each flexible sheet adapts quickly to the contours of the work piece - continuously exposing fresh, sharp grit for extended product life The controllable aggressiveness, working speed, and low cost of the wheels make them superior to wire brush, grit-impregnated plastic, fibrous and setup wheels in a wide range of applications.