Check the listing for details. CAD Audio 631L Noise Cancelling Dynamic Palmheld Microphone with Talk Switch, 10. Condition: New. Listed at 59.00 USD. The CAD Audio 631L is designed for close talking, handheld applications in quality sound installations where background noise is a problem. The frequency response, especially tailored for voice communications, provides a crisp, clear, highly intelligible sound with 360 degrees minimization of background noise. A soft lip guard is positioned to assure proper close talk voice spacing by the operator.The dynamic cartridge has a strong polyester diaphragm which resists moisture, temperature extremes, most acids, alkaline and solvents. Molded in high impact Cycolac, It comes with a permanently attached, heavy duty, four conductor, two shielded, coil cord. The low impedance has a DPDT long life, trouble free switch and is factory wired normally open.