Abstract: A panel with a counterweight for opening and closing and/or bridging an opening or a space. In a preferred embodiment the construction is such that when the panel is in its closed position, the counterweight lies substantially in the same plane as the panel and relative to the pivot the counterweight extends in opposite direction to the panel; when the panel is in the open position, the counterweight lies mainly in the same plane as the panel and relative to the pivot said counterweight extends in the same direction as the panel.