Each of these transparencies were originally used by the US Air Force in presenting safety procedures and hazardous materials training to firefighters (then, firemen) in the 1950s. Each of these was blank - ready to use for additional information during the presentation.
Each transparency measures 10-3/8 inches long by 8-1/4 inches and has rounded corners. There is black border around each one. At the tip of one is clear arrow - apparently to help the speaker point this in the proper direction. On one side of the transparency, the black border is matte, on the other side is shiny.
We think this would be great for a collage or altered art project. We'd venture to guess that there aren't too many of these around.