The 500T features a noise-cancelling microphone and is extremely resistant to interference, hum, and squealing induced by 400Hz power systems. The 100T effectively cancels noise in noisy environments and minimizes popping, hissing, and breathing sounds for clear communications. A microphone gain trimmer is accessible through the side of the microphone housing by removing a small covering label. Output can be increased by adjusting the trimmer. The 500T microphone is approved for aviation use under FAA TSO C58.