The present invention is to provide a kind of first-aid gas mask, which uses an air filter to filtrates toxic gas and to further let the well filtrated gas be delivered to the transparent cover around the mouse and nose of the user for inhalation, which transparent cover is having an elastic band made...http://www.google.es/patents/US5003974?utm_source=gb-gplus-sharePatente US5003974 - First-aid gas mask
