3M(TM) Flexible Diamond Hand File 6210J, 1 3/4 in x 1/2 in M40 Micron, 10 per box 1 box per case Grind hard to cut materials, fine finish delicate surfaces, bevel edges, remove burrs, sharpen tools. Use wet or dry. Ideal on small, difficult-to-reach areas. For stone, metal, glass, ceramic, carbide, composites. Lightweight, rigid plastic handle.