Feature: Size: 100x20x16mm Design easy to use. No experience necessary. Sharpening angle guide is accurate which can guide perfect blade. Unique ceramic protective layer for durable use. Using Instruction: 1. Fix angle guide to the appropriate location of knife blade. 2. Both hands hold the handle and the back of the knife, ceramic part contact the surface of whets tone or diamond, make knife blade into a fixed angle, move the blade, back and forth over the sharpener by using little pressure.