Got this sharpener yesterday and have already sharpened all the knives in the house. I immediately ordered a Lansky Quadsharp. By using these two products I have been able to restore amazingly sharp edges to all my knives. One of my knives has been abused over the years and had trouble cutting soft butter, now I can shave the hairs on my arms with the same knife. I will be ordering at least 3 more of each of these items to have them in different places to always have a sharp edge. Quadsharp is used to re-profile the edge of the knife to maintain the edge, C-Sharp is used to make that new edge amazingly sharp. Definitely recommend buying both products together.