Professional Knife Sharpener for Straight and Serrated Knives, 2 Stage Diamond Coated Sharpening Wheel System, Sharpens Dull Knives Quickly, Safe and Easy to Use

After following the instructions and using this product once, I am returning it. I used it on a moderately sharp Cutco chef's knife. The 20 strokes on each wheel did nothing so I tried it 20 more times and still nothing. I have and old Smith's sharpening kit but the ceramic rods are broken. What was left of the Smith's kit sharpened the knife better.