This is a side mounted, top hung, adjustable wardrobe door roller assembly with a single 3/4 in. flat nylon wheel for the back door panel. The stamped steel bracket assembly is adjustable and has a 3/4 in. offset. It fits 3/4 in. to 1-3/8 in. thick doors. Used on Atlas closet door systems as well as a variety of other wardrobe door manufacturers. For other offsets see Prime-Line parts N 6627 or N 6628.