Sherman thought he was sending an SOS signal to the world by activating an "epirb" -- short for emergency position indicating radiobeacon -- which is a satellite-connecting beacon that resembles a floatable walkie-talkie.

CNN: Shipwreck survivor recounts drama on high seas

The floatable bags operate in extreme temperatures of -22F to 140F and protect against water submersion for 30 minutes at a depth of 1 meter, also designed with room to accommodate a few small items such as credit cards, bandages, etc.

ENGADGET: SpareOnePlus adds location tracking, audio alerts, keeps the 15-year life on a single AA battery eyes-on