3M Trizact cloth belt 237AA uses proprietary microreplication technology where micron-graded aluminum oxide particles are formed into tiny pyramids of abrasive mineral and then coated on an X-weight cloth backing. As these pyramids wear, fresh, sharp mineral is continually exposed to produce a consistent cut and a predictable, fine finish. - Self-sharpening pyramids start sharp, stay sharp and run cooler than conventional abrasives. Flexible backing for consistent finish over contours. For intermediate finishing and fine polishing prior to plating or buffing.