Aluminum oxide is durable and the most common abrasive grain * Cloth backing is stiffer, tougher, and thicker than a paper or film backing * Flap wheels conform better to the workpiece than a disc, and are commonly used for grinding and finishing on irregularly shaped workpieces * Round shank for use on a wide variety of toolholding systems * Micro mini flap wheels are mounted on 1/8" diameter steel shank for use with many toolholding systems