Kriss Kross razor strop

Found this today. It is really slick. You put the razor blade in as shown, then crank the handle. It turns a leather disk inside against the blade, and then flips the blade (it's part way through the flip in the second pic) over to do the other side. It keeps flipping as long as you keep turning., and has adjustable pressure on the blade. Really neat piece of mechanical art, and I will be using it in the shop, I think.