A modular helmet-mask assembly for protecting a user's head and face from hazards such as from chemical and biological warfare agents. The invention includes an impact resistant helmet; a face protection assembly, which can be attached and detached from the helmet; and a transparent, impact resistant...http://www.google.com.tw/patents/US7934497?utm_source=gb-gplus-share專利 US7934497 - Modular helmet-mask assembly
