The Swiss Watchmaker Breitling makes watches that are popular with aviators. One of their watches is also popular with some boaters; It’s called the Breitling Emergency.
The Emergency has a built in ELT (emergency location transmitter). If you become stranded as the result of a downed aircrash or a boating mishap, you simply unscrew the protective cap and pull out the antenna. The Breitling will broadcast a signal on the 121.5MHz aircraft emergency frequency for 48 hours. How James Bond is that?
You can get the Emergency in gold, white gold, or stainless. There are different models; some are more dressy and others are more sporty.
The analog/digital models feature calendar and 1/100th sec chronograph functions. It has a rotating bezel, a sapphire crystal, and its water-resistant to 3 bars (about 65ft underwater) even while transmitting.
The watch comes with a video to explain the use and function of the transmitter. DO NOT JUST “try it out”. There are heavy fines for sending a distress transmission in a non-emergency situation and in some cases you’ll get both fined and charged for the cost of deploying rescue personnel. Besides, what are your neighbors going to think when people start rappeling out of a Coast Guard chopper onto your roof.
Since it’s transmitting range is limited to 100 miles and can reach aircraft flying up to 20,000 ft, it’s not a substitute for a full GPS Sarsat locator. But it does work and it has saved lives, so it’s not just a great conversation piece. It could be your backup locator if you really want to be found.