All Junior Posters  have a 5' H x 11' W  live copy area to allow national showings. The ad design size in LA is the same in NYC. Our industry has not standardized the installation method. Most Junior Posters started out pasting paper inside the trim on the face. Now most Junior Posters use vinyl. Eco-Flex and various weights of vinyl such as 13 oz. white-back vinyl are used. Some poster printers finish the ads on the vinyl with pockets which the billboard installer inserts fiberglass rods into. Others use springs or other hardware to attach the vinyl inside the trim. Billboard operators sometime cover the whole trim with a "vinyl wrap". This method is usually used if the ad is going to stay at one place for a long period of time. Some Junior Poster markets offer a rotation plan where each poster ad is removed and posted in a new location every few periods. This allows each advertiser to reach various traffic patterns and increase the value of their buy.