D 1981 is a C tab tandem roller assembly with two 1-1/8 in steel ball bearing rollers installed. The C tab fits around the corner screw and captured by the side stile and bottom rail as they are drawn together. The adjustable stamped steel housing is 11/16 in wide with 7/8 in dimple width, 1-1/16 in tall and 3-1/8 in long. Used by several patio door manufacturers. For 1-1/2 in roller version see D 2057.