Mask includes support member with head band arranged horizontally to fit head of wearer. Conduit sections are secured to each side of support member, and flexible ventilation conduit is connected to exhaust means. Transparent face plate is held to support member in spaced relation to wearer's head. Aperture...http://www.google.fr/patents/US3955570?utm_source=gb-gplus-shareBrevet US3955570 - Surgical exhaust mask
