Small enough to fit in the pocket of your buoyancy compensation device, the Nautilus LifeLine Marine Rescue GPS is a waterproof personal signaling device that can transmit a distress signal to any commercial ship or most yachts within 34 miles of your position.

The LifeLine requires no special or dedicated base unit, registration, subscription, or service fee. Simply flip the cap open and press the red button to issue a distress call using the marine automatic identification system (AIS) and digital selective calling (DSC) technologies. Its built-in GPS can pinpoint your position to within 4.9'. The unit is depth-rated to 450', so you can have it with you while you dive, but the cap must be opened at the surface. It will run for up to five years on two CR123A batteries.