This is actually a theater window card … I have one somewhere in my treasures. They’re 8.5″x11″ and there was a series of about 12 that WB distributed to theaters when The Exorcist was released.
dsea, the window cards were usually posted throughout the theaters in multiplexes. It was another way to entice more moviegoers to see the film. Plus, they did actually use them in the windows and on doors on the outside of theaters. Ah, the good old days. 🙂