The window or door has two sashes directly adjoining each other in a fixed frame with no fixed centre posts. A movable closing stud is brought in and out of locking engagement with a closing plate (8) through a drive rod (9). The closing plate (8) has a base body (13) and clamping body (14). The base body is freely displaceable in the longitudinal direction of the fitment and is clamped between the clamping body and rail (7). The clamping body engages in an oblong hole (18) of the body, fits stepwise into the rail (7) and is screwed to the vertical beam of the sash (2) through the rail (7) and drive rod (9).
