This is a single wheel; top hung, side mounted adjustable roller bracket with a 1 in. convex nylon roller that fits onto the front wardrobe door panel. The stamped steel adjustable bracket has a 1/4 in. offset and fits onto a 3/4 in. to 1-3/8 in. thick door. Primarily used on Cox door systems, it may also be found on a variety of other wardrobe door manufacturer's doors.