DescriptionHat advertising card meant to be placed inside a hat both to identify the owner and promote the store that sold the hat. This card was promoting a store at 4 John Street in New York City, which featured Knox Hats. The owner's name and address would be written in the blank space. These cards were frequently used in the 1940s. They also came in handy when you left your hat in the coat/hat check, to prevent confusion when the owner came to reclaim it.