The AquaLink™ is small enough to be easily carried in a pack or pocket or can be worn on deck, at the helm, in quarters or on a life vest and will float if accidentally dropped overboard. Performing a full functional self test of the PLB?s internal circuitry, battery voltage & power, and 406 MHz transmission gives you the peace of mind knowing your PLB will work the moment you need it to the most. ACR Exclusive: Built-in GPS acquisition test mode allows you to test GPS functionality up to 12 times over the life of the battery life.