The AirLine headset transmitters feature the Samson Qe Fitness and QV10e Vocal microphone elements. The Qe and QV10e headsets were designed to go around the back of your head rather than over the top. This allows the transmitter to be attached directly to the headband, out of the way and completely unobtrusive, while being comfortable and secure during performances or group fitness classes. Both the Qe and the QV10e are designed with unidirectional microphones and cardioid pickup patterns that reject feedback. The Qe Fitness headset is ideal for group fitness instructors who need a durable headset that will remain in place despite repetitious movement. The QV10e Vocal headset has a microphone element that's perfect for singers who need hands free performance. Both transmitters offer 14 hours of operation on a single AAA battery.