This United States Postal Service sign is 1 of 9 signs that were made for the United States Postal Service experimental signs. My uncle handed it down to me after retirement at the Postal Service. He was told that 9 signs like this were made and only a few survived and the rest were melted. I don't know much about it hoping you can help inform me more about it. Thank you!

36 inches in height 34 inches width 2 inches thick