These microphones are linear, noise-canceling, dc-powered, high-gain microphones designed for use on military headband-type or helmet configured headsets at low altitudes, pressure-type oxygen masks at altitudes where the use of oxygen is required, and CBR masks for special missions. The microphones are intended for use as part of existing military and future airborne and ground communication systems that will provide communication of high intelligibility under the extreme noise conditions encountered in military environments.