Regular Solar Screens normally have 1 crossbar or none at all depending on the actual window. Your window will dictate the proper “crossbar” or lack thereof in order to give the screen the support it needs while keeping the full view through the window without seeing the solar screen’s support bar.
Operational windows will normally have 1 crossbar, usually horizontal, on windows that open. The bar is placed on the solar screen where the natural break of the window is. Some windows that open “side to side” will have a vertical bar at the natural break unless the window has a duel track system. Then there will be two individual solar screens made to fit in its tracks.
Non-operational windows, windows that do not open, will normally not have any cross bars to keep the full view out of the window. The window itself always dictates the proper amount of support bars needed and where they go