About Knife Sharpener: Believe it or not, a dull knife is one of the most dangerous objects in your kitchen. When a blade isn’t sharp enough to properly cut food, it can easily slip from your control, nicking your hands or fingers. Keep cooking fun, safe and healthy with the Knife Sharpener by Kit challenge! Our 3-step system begins with a diamond rod slot that gently repairs and straightens damaged blades. You can even use it for ceramic knives! Next, tungsten steel provides coarse sharpening that restores the blade to a V-shape before the 3rd slot creates a stunning polish.