Knife Sharpener, Smart Sharp by MRTONG, No1 Choice for Sharpening Kitchen Knives. 3-in-1 Manual System for All-Sized Household Knives.

Tried it on one of our old knives. Before using the sharpener I tried the knife on a tomato. It cut the tomato but after a few strokes. Our new sharp knives cut on the first stroke. I then sharpened the old knife following the instructions and tried it on a tomato. It was no better, may even have been worse.Not keen to try on newer knives just in case it dulls them.Not impressed. I'll go back to using a steel.

Perfect, bought with a new set of knives. Easy to use

The product is a life saver. Now we don't have to buy new knives when the old ones get blunt.