This extra long Diamond Bench stone offers the ultimate in sharpening technology. It features multiple layers of micron-sized mono-crystalline diamonds bonded in nickel to a flat metal surface. The unique overlappying oval hole design speeds sharpening by collecting and holding the metal filings which ordinarlily build up during the sharpening process. This allows the sharpening surface to remain clean and clear and speeds sharpening. This stone is excellent for use on large knives and woodworking tools.