The Nautilus Marine Rescue GPS is less than half the size of our original radio and extremely easy to use. Just undo the latch and open the device, turn it on, remove the antenna retainer, and press the red button. That's all it takes! Your GPS position, accurate to 1.5 meters, and a man overboard distress message will be broadcast up to 34 miles away, along with a special DSC message to the marine radio on your own vessel. The Nautilus GPS floats and is waterproof in all sea conditions. Simply keep the o-ring clean, and you can rely on it for the next 5 years without worry.