Safe and easy to use， this two-stage knife sharpener requires nothing but a few easy strokes to keep blades sharp. The first-stage carbide (coarse) sharpens dull edges. The second-stage ceramic (fine) provides a polished， razor sharp edge. A reasonably sharp knife may only require this light honing. Can be used for serrated and scalloped edges (ceramic fine-stage only). Clean with a damp cloth or mild brush， wipe dry. Do not rinse with water. Measures 9x3 x1.5".