The electro-voice model 903E condenser handheld microphone is designed for use in high noise environments where high speech intelligibility is desired such as in aircraft cockpits, passenger cabins, control towers or terminal areas. The electret element virtually eliminates EMI, RFI, and magnetic signals channeling the full power of your communications system into crisp, articulate voice transmission with the RTCA frequency response. The microphone is recommended for advanced technology air transports employing flight instrumentation systems (glass cockpits). Its proven electret technology will not decay or deteriorate in any way over extended periods.