D 1794 This is an adjustable diecast plain back patio door roller assembly with a 1-1/4 in. concave steel ball bearing roller. Its plain back diecast housing is 1/2 in. wide, 1 in. tall and 1-9/16 in. long. There is a 10-32 threaded mounting hole in the back end as well as on to top of the housing. There is an adjustment screw in the back end. 1-1/4 in. Concave (grooved) Steel Rollers. Ball Bearing. Diecast Plain Back Housing. 10-32 threaded mounting hole on the back end and a 10-32 threaded hole on the top of the housing.. Housing is 1/2 in. wide, 1 in. tall and 1-9/16 in. long (not including the inner roller housing). Adjustable. Used on metal framed patio doors