The Angle Adjust Manual Sharpener is the FIRST adjustable sharpener of its kind; the sharpener has unsurpassed technology that allows you to sharpen the knife to the original factory angle. It includes 3 slots for sharpening. The fine slot features ceramic rods for finishing the knife edge and everyday light honing and maintenance of an already sharp knife. The coarse sharpening slot features diamond stones that are used to sharpen dull or damaged knives. The serrated slot is a fixed slot designed for sharpening most styles of serrated knives. To use the sharpener simply select the desired angles and pull the knife through the slots 10 + times. (The number of pulls depends on the sharpness or damage to the knife.)