This is a F-tab patio door roller assembly with a 1-1/4 in. concave steel ball bearing roller. When the corner screw passes through the F-tab the assembly is captured by the side stile and bottom rail as the screw draws the two sides together. The housing is 11/16 in. wide and 1-3/16 in. tall with a dimple width of 7/8 in. used by Northrup and a variety of sliding patio door manufacturers.