We're suckers for devices that solve a very specific problem, and these slippers do precisely that—the problem in this case being that most nefarious of crimes, slipper theft.
Each slipper has a ring at the back that you slip the legs of a table or chair into; an alarm will ring in the event that a slipper is taken and the ring pulled out. Ingenious? Sure. Useful? Not so much.
Antitheft Slippers [Seihin-World]