This Firepower 1423-2160 Mounted Flap Wheel is 60 grit and measures 1" x 1" x 1/4". Firepower flap wheels are 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. Max RPM: 25,000.