Prime-Line Products N 6503 Closet Door Tandem Roller with Back, 1/2-Inch Offset and 7/8-Inch Nylon,(Pack of 2) 7/8in. O.D. Twin wheel 1/2in. Side mounting to back of door Offset adjustable bracket Round edge nylon wheel Fits 3/4in. to 1-3/8in. thick doors