The Chef'sChoice Pronto #463 applies flawless and durable 15 degree edge in seconds and will put a better than factory edge on your 15 degree class knives! The Chef'sChoice CrissCross sharpening technology uses 100% diamond abrasive wheels that simultaneously sharpen into and out of the knife's edge on each side of the blade for a superior, burr-free razor sharp edge with a durable arch-shaped finish. On opposite sides of the edge, the sharpening lines combine to form the ""crisscross"" pattern that shapes the microscopic teeth.