I believe it is a special clamp that holds a small square for you to use your 90 degree cutter and come along and cut a V groove in the square. See the 90 degree channel? See the screws? You put the square in the groove, tighten down to secure it, secure the jig to your lathe or milling machine and cut the groove. Repeat the process after gluing up another square in the square you just cut, and you have a recut fixture that lets you make your recut point outside of the cue.
There was a post made by the inventor a year or so ago. I don't own one so I could be wrong about the details, but I believe that is a general description.
Kelly
