The Kai diamond and ceramic retractable sharpener sharpens knives quickly and easily with a simple 3-step process. It's ideal for left- or right-handed use. The sharpener is already set to the 16-degree angle required to sharpen any Kai straight-edged, double-bevel blade. Just pull the knife through the first slot for rough sharpening. Refine the edge by pulling it through the second slot, then finish by pulling it through the third slot. Your knife's razor sharpness is restored and it's ready to go to work in your kitchen. Comes with simple instructions. Includes Retractable cover for easy, compact storage. Please note, this sharpener is not designed for serrated, single-bevel, ceramic, or Titanium blades. It should not be used on blades with nicks or chips, or with blade stock wider than 3. 5 mm.