A personal locator beacon [PLB] is a small device that lets you send a distress signal from anywhere in Australia or the world via a satellite network. The device will transmit your location to the search and rescue authorities in case of an emergency
They can be used to send a personalised emergency distress signal or messages when you are in remote locations and out of the range of mobile phone coverage. There are a large number of PLBs or satellite communicators that use the Iridium Satellite Network or the Globalstar Satellite Service. Two examples are ZOLEO, which uses the Iridium Service, and the Spot Gen4 or Spot X devices, which use the Globalstar Services. Both require a subscription to use these devices.