This is a side mount, top hung, adjustable wardrobe door roller assembly with a single 7/8 in. convex nylon wheel for the back door panel. The stamped steel bracket assembly is adjustable and has a 1/2 in. offset. It fits 3/4 in. to 1-3/8 in. thick doors. Used on Atlas closet door systems. For the front door panel use Prime-Line part N 6667.