A helmet in which the crown and frontpiece are blocked out of rawhide, and the front shield is fitted with two mica windows in hinged aluminum frames. It has a twin-tubed air feed on each side of the helmet and a valve for the escape of excess and vitiated air. Air is supplied through an armored hose from double-acting bellows or a blower worked by a second person at the fresh air base. Airtightness is obtained by means of a soft leather apron secured in position about the neck and shoulders. Illumination is provided by portable electric lamps, and communication with the wearer by an approved type of mine telephone.