Motorola RMN4048A Temple Transducer

The temple transducer allows communication even while wearing earplugs, so that you can still hear machinery, warning alarms, traffic and even casual communications without risking damage to your ears in high-noise environments. It uses receivers on your temple that convert audio signals into sound vibration and transmit them to your inner ear. It has a push-to-talk switch and boom microphone, and it’s rated intrinsically safe with an FM radio.