15 Trizor XV EdgeSelect Professional Electric Knife Sharpener with Diamond Abrasives for Straight and Serrated Knives Patented Sharpening System, 3-Stage, Gray, Made in the USA It is crucial to realize that converting your knife will require substantially more sharpening time to get a trizor edge. Swipe the knife 20 times on each side for level 1. Swipe the knife 15 times on each side for level 2. Swipe the knife 5 times on each side for level 3. The manual shows how to use each type of knife correctly. The manual also has suggestions and tips.