3M 0.3 Micron Microfinishing Lapping Film Sharpening 8 1/2" x 11" Sheet with PSA Backing 8 1/2" x 11" 0.3 micron microfinishing sheet. Very fine 0.3 micron aluminum oxide sheet is the equivalent of a 12000 grit waterstone. Pressure sensitive adhesive backing. Sold in single sheets.