This Case Cutlery EZ-Honing Sharpening System features three Arkansas oil stones mounted on a hardwood block: a Silicon Carbide (coarse grit), soft arkansas oil stone (medium grit), and hard arkansas oil stone (fine grit). Includes honing oil and plastic carrying case with complete instructions. It is a pure form of genuine Novaculite rock, found only in the area surrounding Hot Springs, Arkansas. With light Honing Oil and smooth even strokes, this rare stone can put a quality edge on any blade. This is the Aston Martin of sharpening stones that will last a lifetime! Variations in color are entirely the work of nature and in no way affect the quality of the stone.