WW2 RAF uniform buttons that become a compass for soldiers left behind enemy lines pic.twitter.com/OmyoB3YZC1
— Lost in history (@lostinhist0ry) July 28, 2022
This tiny button is actually a compass. During World War II, Royal Air Force crews were often equipped with these buttons in their uniforms. If they were shot down at night and needed to figure out their directions, they could remove the buttons and balance them to on pins and see which way the buttons turned.
Some of these buttons were on jackets, but this one was on a trouser fly. The Museum of Radiation and Radioactivity explains that dots marked on the buttons provided a marker that would point north. Doreen Galvin writes in Arts to Intelligence that the Germans eventually discovered the nature of these buttons, so RAF designers switched the direction of the indicator dots.