Abstract: A respirator face mask formed from a silicone or other vulcanized rubber with a multi-compound curved face seal having a superior configuration for facial fit. The mask is held by four support buttons and two straps attached thereto having a reverse leverage pulldown effect to pull the mask into contact with the facial area. The four attachment means for the straps are eccentric buttons having an undercut that overrides a loop that can be easily disassociated when the attachment loop is reversed and pulled over the button. A concave configured sealing diaphragm on the exhalation valve provides for substantially uniform opening with less effort than is normally encountered in such valves. A staggered anti-inversion rib on the concave underside of the exhalation valve prevents the diaphragm from inverting to a convex configuration. The valve includes an exhalation valve stack and vent that can be covered at a sharply chamfered opening to provide for a pressure fit test.