The forehead mic transmits your voice by the vibration of your skull. It transmit crystal clear sound without the need to talk before a boom mic. It is attached to an elastic Velcro strap that suits head sizes from 12 to 25 inches.
Mechanical vibration from earbone => electric signal => transmitted to radio transceiver
Since the speaker/mic is hidden in your ear canal, it is not sensitive to any background noise. This is exceptionally ideal for usage in high ambient environment such as driving, riding motorcycles and bicycles.