I've tried a lot of different kitchen knife sharpeners, and this cheap one is my favorite

I've been using a Kitchen IQ Edge Grip 2-Stage Knife Sharpener  for years and it's my favorite knife sharpener.  I like it because of the way you hold it with one hand along the edge of a kitchen counter and with the other hand you draw the knife through the slots. It's a safe way to sharpen a knife and I don't see how someone could make a mistake and hurt themselves. One slot is "coarse" and the other is "fine." I typically use the fine slot every week or so to restore the edge on a knife. I rarely use coarse because it removes quite a bit of steel from a knife, but sometimes that's just what's needed to sharpen a dull knife.