Patent ID: 7028688

Claim:
An operationally adaptable chemical-biological protective mask, comprising: a head covering effective for fully covering the wearer's head, wherein the rear and top sections of said head covering comprises a hood and the front of said head covering comprises a face piece; wherein said face piece has at least one visor effective for providing a visual field of view to the wearer, said face piece is securely attached to said hood, and wherein said face piece includes a face seal for sealing the face piece to the wearer's face; a nose cup positioned within said face piece to fit over the mouth and nose of the wearer, said nose cup having an inlet valve, an exhalation outlet valve comprising a valve which can be closed by the wearer, and a purge valve for directing air into said hood when said outlet valve is closed by the wearer; an air supply port positioned at the rear of said hood for permitting outside air to be supplied to the inside of said head covering; one or more rear filters mounted in combination with said rear mounted air supply port, wherein said one or more rear mounted filters cleanse air flowing into said head covering; and, ducting adjacent to said head covering and connecting said rear-mounted air supply port to said face piece, said ducting providing a conduit for filtered air from said rear mounted supply port into said face piece.