Use on extremely hard materials for repeatable, precision finish. Combines micron
"For diamond lapping on extremely hard materials such as ceramics, stone and glass, choose 3M™ Diamond Lapping Film 661X. Our films cut fast for a more efficient process. A tightly graded diamond mineral, precision coated on a 3.0 mil polyester film backing, they provide a flat surface, sharp edges and a uniform finish. Available in discs, sheets and rolls – cut to your requirements."