US collar insignia as worn by Officers in the Women's Army Corps (WAC/WAAC) during WW2.
The auxiliary women's corps of United States Army (WAC) was founded in May 1942. Initially the WAAC not have the military status until July 1943. These were the first women other than nurses who served in the US Army. Women anonymously WAC were very important during WW2. Making multiple jobs as mechanics, flight controllers, drivers, electricians, the list is endless, because they performed an infinite number of tasks.