Norton 1-by-2-by-8-Inch Fine/Coarse India Combination Oilstone, Red 100/320-grit combination oilstone is made of aluminum oxide with 100 grit on one face for repairing steel cutting edges and 320 grit on the opposite face for sharpening and maintaining them; it produces durable, smooth-cutting edges. This is my all around sharpening device, not only for my kitchen knives but  for my wood working chisels and cutting devices! You must use mineral oil and never cooking oil with this sharpening stone.