3M(TM) Roloc(TM) Flexible Diamond Disc 6234J, 1 1/2 in x NH M250 Micron, 10 per case For hard to grind material, stone, glass, ceramic, metal, carbide, composites. Metal plated bond securely anchors micron graded diamonds to backing. For flat, edge, contour grinding and polishing. Heavy duty, water resistant, polyester backing.