Our 3M⢠Cubitron⢠II Hookit⢠Paper Disc 732U features 3M Precision Shaped Ceramic Grain, a revolutionary advancement in abrasive technology. The triangular shaped ceramic mineral is designed to slice through the substrate, rather than gouging or âplowingâ like conventional abrasives, resulting in a disc that cuts up to 2x as fast and lasts up to 4x as long as conventional abrasives.