If you are getting into serious knife sharpening, you need one of these. This little microscope lets you see what your knife edge really looks like. You will be surprised to see all the tiny scratches made by the sharpening stones. You can clearly see the jagged edge and understand why you need a strop. Because of the simple optics, the image you see is reversed right-to-left and up-to-down, but you get used to that pretty quickly.