headgear in the form of a helmet and equipped with an electroacoustical headset consisting of two earphones and either a microphone with a low sensitivity to ambient noise or two laryngophones. Communications helmets are intended for personnel who work under very noisy conditions, for example, in airplanes or tanks.
The helmet, which is made of fabric or leather and is lined with acoustic insulation, covers the entire head except the face. When laryngophones are used, the helmet also covers the neck. The earphones are snugly fitted into acoustically insulating pads sewn into the helmet; the edges of the pads are pressed against the head around the ears. The microphone is in a special holder near a corner of the mouth. The laryngophones, which are usually employed at noise levels exceeding 120 decibels, are fastened to the neck at the larynx. The headset is connected to equipment for intercommunication, outside communication, or both.