Prime-Line Products N 6509 Closet Door Roller with 1/2-Inch  Offset and 3/4-Inch  Nylon Wheel,(Pack of 2) Single wheel Side mounting 1/2in. Offset adjustable bracket for back door 3/4in. O.D. round edge nylon wheel Fits 3/4in. to 1-3/8in. thick by-passing doors up to 50 lbs. each