specially adapted for insertion in flat panels, e.g. in door or window-pane

Full Title

Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening > Air-flow control members, e.g. louvres, grilles, flaps or guide plates (F24F7/013, F24F13/06 take precedence) > specially adapted for insertion in flat panels, e.g. in door or window-pane