Norton JM3 1/2 x 2-1/2 x 11-1/2" Coarse Grit Crystolon IM313 Replacement Oilstone 100-grit for repairing cutting edges Silicon carbide sharpens to moderate tolerances with minimal loading when it is more important to sharpen the blade quickly than to produce a fine cutting edge Prefilled with oil to allow lubricant to stay on surface during sharpening 1/2 x 11-1/2 x 2-1/2 inch (H x W x D) size makes this suitable for use as a bench sharpener for knives and tools Oilstone is more durable and harder than a waterstone