This is a combination bench stone produced in electric furnaces. This Crystolon stone is made of silocon carbide and is gray in color. One side of this fast cutting stone is coarse and is used for sharpening severely dull knives, repairing nicks, chips and damage from improper sharpening and generating new edge angles. The other side is fine and is used to sharpen slightly dulled edges and upgrade the finish left by a Coarse and Medium Crystolon stones. It's dimensions are 6 in. by 2 in. by 1 in.