Prime-Line Products D 1554 Sliding Door Roller Assembly with 1-1/4-Inch Steel Ball Bearing 1-1/4in. O.D. Steel ball bearing center grooved roller Housing dimensions: W: 9/16in. L: 2-1/8in. H: 1in. Overall thickness: 13/16in. Adjustable steel housing assembly Fits Acorn door and other manufacturers