The Post Office Department’s public service advertisement poster (POD Poster 167.A) released in August 1966 promoted ZIP code use. It features Mr. ZIP with his iconic letter carrier’s uniform and satchel. Unlike advertising a new service or announcing a regulation, bringing ZIP codes to the public’s attention centered on the difficult task of changing people’s behavior. As the envelope Mr. ZIP is holding in this poster shows, the Department asked the public to write the ZIP code in both the return and main address portions of the envelope. Mr. ZIP is depicted as speeding along with the newly-styled, addressed envelope. The image reinforced the poster's text message--“Help improve mail service by adding zip code to every address. Add zip to your return address too. Then others can zip their letters to you.” The poster appeared on public transportation.