Watchlords

"There are certain watches that have become legends of sorts amongst collectors and enthusiasts. One watch that is indisputably in that category is the Breitling Emergency. The watch is powered by an extremely accurate quartz movement and has a combination analog/digital display, but what really sets it apart is the concealed emergency locator beacon that is hidden behind a screw-down cap in the lower right lug. There have been a handful of stories about this unique watch actually being used in the field to save lives, but for most owners this feature remains dormant and unutilized for the duration of the watch's life. The result is that the specifics of exactly how this watch works can be a little confusing."

https://www.hodinkee.com/articles/breitling-emergency-orbiter-three-explained