This was lent to me by a buddy whose father worked for Eastman. He didn’t have any idea of the date range.
It’s 1 3/4″ wide and 2 1/2″ tall. It doesn’t carry a sterling mark. There are letters on the reverse but they’re badly worn. I can make out “DEPT”. It has a fairly heavy duty pin on the reverse. It weighs 20 grams.