Accusharp, Tri-Stone Knife, Sharpening System, Easily Sharpen & Hone Any Straight Edge Blade With Ease, 3 Stone Surfaces Include: Coarse Diamond, Medium Alumina-Oxide & Fine Ceramic, Provides Extra Durability & Safety On Any Surface With A Rubber Grip Base Which Prevents Sliding While Sharpening & Honing Your Knives, Sharpener Base Can Be Mounted To Most Countertops For Extra Stability, Angle Guide Provided To Assist In Maintaining A Consistent Angle While Sharpening.