This specification covers headsets and headset-microphone assemblies intended for use in medium
ambient noise level environments of 85-105 dBA SPL (Sound Pressure Level). These headset-microphone
assemblies use dynamic earphones of the moving coil type that transform electrical energy into acoustical energy. A
complete assembly includes headband, earphone(s) mounted in rigid earcups, with cord assemblies to meet
requirements of various military service activities. The assemblies include, as required, a noise canceling
microphone and boom.