Bone conduction microphone
A bone conduction microphone (also known as a skull microphone or skull microphone ) is a special sound pick-up similar to the larynx microphone for speech communication in extremely noisy areas or when other types of microphones are seen as a hindrance when working under full protection, such as fire brigade operations. The bone conduction microphone is usually pressed against the top of the skull by a protective helmet and mechanically picks up the sound transmitted by bone conduction as a pickup . In advanced communication systems, airborne noise and interference are digitally filtered out and the processed signal is used for communication.