I found a bag of these union pins last year at the World's Longest Yard Sale!! The pins dated 1966 to 1979.
Just looked up the meaning to the initials...
International Brotherhood of Teamsters, Chauffeurs, Warehousemen, and Helpers of America.
The small pins were quite colorful and interesting to me. Bought them all and mounted them on a vintage button to create a fun new ring.
Little bit of vintage, blingage history!