Ergo Chef black FASTEDGE Two stage manual pull through knife sharpener will sharpen & hone straight edge knives and even hone serrated knives. It has a non-slip base to safely sharpen & hone your knives. It cuts an smooth 18 degree edge with the Coarse Carbide inserts, then can finely hones the edge with the ceramic rods for a perfectly sharp blade with just a few passes. Our research has shown that an 18 degree edge is most versatile and durable for all types of knives giving you a smooth cut through all types of food. This Sharpener takes the guess work out of angles and makes it simple for anyone to sharpen there dull knives. Environmentally friendly by design to re-use the handle & simply change out the replacement cartridge when needed (Usually 1-2 years depending on use).