My mother, Cyril F Speizman, worked in the Procurement Division of the Smithsonian Institution. As they were compiling items for the dog tag display in the then new Museum of History & Technology, they realized that they did not have a dog tag that belonged to a Woman Marine. I, at that time, was a captain stationed in Quantico, VA and she volunteered one of mine. I retired as a Colonel in 1992. The "S" at the bottom right corner indicates the gas mask size. The exhibit was on display for many years in the Museum of American History.