This sharpener is designed to work with any Kai straight-edged, double-bevel blade, and the 3-step process couldn't be simpler. Just pull the knife through the first slot for rough sharpening, the second slot for refinement, and the third slot for finishing. And voila! Your knife will be razor-sharp and ready to return to work in no time. One thing to keep in mind - this sharpener isn't designed for serrated, single-bevel, ceramic, or titanium blades. And if your blade has nicks or chips, or if the blade stock is wider than 3.5 mm, it's best to avoid using this sharpener. But as long as you have the right type of blade, the Kai Diamond and Ceramic Retractable Sharpener is an awesome tool to have on hand. It even comes with a retractable cover for easy, compact storage. So why not give it a try and see how easy it can be to keep your knives sharp?