High Quality Content by WIKIPEDIA articles! Avalanche transceivers or avalanche beacon are a class of active radio beacon transceivers operating at 457 kHz and specialized for the purpose of finding people or equipment buried under snow. When the owner sets out on a skiing descent, the transceiver is activated, causing the device to emits a low-power pulsed beacon signal during the trip. Following an avalanche, and if the holder of the transceiver is safe has not themselves been caught by the avalanche, they may switch the transceiver from transmit into receive mode, allowing use as a radio direction finding device to search for signals coming from other skier`s transmitter beacons who may be trapped. A 457 kHz beacon is an active device that requires batteries. Ski suits may also contain a passive RECCO transponder sewn-in to the clothing.