Redundancy is key to avoiding accidents on the mountain as much as it is to surviving them. The best beacon in the world is still a manmade piece of electronics that can fail at any time, and that's why you need the Pieps Backup beacon. The Pieps Backup beacon operates silently when worn against your body. The backup continually searches for signs of motion and signals from a nearby beacon. If the Backup detects absolutely no motion and can’t detect a signal from your main transmitter, it will automatically activate and start transmitting. If at any time, it detects that your main transmitter is sending or that you are moving, it will discontinue sending its signal to avoid interfering with the search process.