The AccuSharp Tri-Stone Knife Sharpening System provides easy sharpening and honing for any straight-edge blade. AccuSharps three-stone surfaces includes coarse, medium, and fine alumina-oxide stones. This Tri-Stone System provides extra durability and safety on any surface with a rubber-grip base which prevents sliding while sharpening and honing your knives. The Tri-Stone Sharpener base can be mounted to most counter-tops for extra stability. Includes an angle guide to assist in maintaining a consistent angle while sharpening. Grits Coarse 120, medium 180, fine 240.