Ceramic aluminum oxide is a self-sharpening grit that is harder, tougher, and lasts longer than aluminum oxide * 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 * 1/4"-20 threaded spindle for use on threaded toolholding systems * High-performance flap wheel is aggressive and works well for high stock removal