“Easy to use”
This sharpener works well, and keeps a nice, sharp edge on most non-serrated knives. You have two grits - one to grind down the edge, and one to hone it. You count ten strokes on each, and you have a sharp knife!
If you have a knife that hasn't been sharpened for a long, long time, or you have nicks in your edge, you will have to run it through the rough slot a long time. The alternative is to learn how to sharpen on stones, which give you a lot more control, but also increase the chance of making an error.
This sharpener should be used infrequently - maybe once a month or so - and between sharpenings, use a regular stick-style hone to keep the edge sharp.
If you use it more frequently, run the blade only through the hone side. The grinding side will take off too much material.
Search Sears.com
for Chef's Choice Manual Diamond Hone 2 Stage Knife Sharpener prices