A typical hearing loop induction system consists of a microphone or other signal source, a power amplifier to boost the signal, and a loop, or induction "antenna". The loop can be as small as a personal neckloop - the size of a long necklace - worn by an individual, or can be as large as a wire which encircles a room, auditorium or other listening area.
The receiver is most often a hearing aid with a built in telephone coil. Most, but not all hearing aids have a T-coil. Check with your hearing care provider if you are unsure about yours. Listeners who do not have hearing aids equipped with T-coils, or who do not use hearing aids at all, can use special induction receivers with earphones.