Removable Steel Mullions provide single door performance in double door openings with rim devices. Mullions are easily removed by loosening bottom set screw and removing top fitting cover. The top mullion fitting is attached to the frame and is concealed by the fitting cover. The top mullion fitting is attached to the frame and is concealed by the fitting cover. Steel mullions are 2” (51mm) wide and 3” (76mm) deep, with a wall thickness of 1/8” (3mm)