The Chef'sChoice 1520 AngleSelect professional electric knife sharpener is the ideal solution for improved cutting performance on both 15 and 20-degree class knives. Using 100 percent diamonds, the hardest natural substance on earth, our patented abrasives sharpen faster and easier to create a sharp, longer lasting edge. In the final stage, patented stropping disks create an unparalleled polished finish. Precision angle guides ensure accurate sharpening throughout the entire blade length and eliminate any guesswork. This unit is designed to work with both straight-edge and serrated knives.