A respirator mask comprising: a facepiece including an interior surface and exterior surface opposite the interior surface and a regulator engagement region having: an aperture ; and a protrusion proximate the aperture , the protrusion extending a distance from the facepiece exterior surface and including: an apex at which the protrusion extends a maximum distance from the facepiece exterior surface ; a latch activation region that includes the apex and extends in either direction from the apex ; and; a regulator being sized and configured to be received within the facepiece aperture, the regulator including: a regulator body having a facepiece engagement region matably engageable with the regulator engagement region ; a fluid flow path within the regulator body; and a latch within the regulator body , the latch being engaged and actuated by contact with the latch activation region to obstruct the fluid flow path), the regulator being rotatable within the facepiece aperture between a first rotational position and a second rotational position such that rotation of the regulator within the facepiece aperture from the second rotational position to the first rotational position engages the protrusion with the latch and actuates the latch to obstruct the fluid flow path. a facepiece including an interior surface and exterior surface opposite the interior surface and a regulator engagement region having: an aperture ; and a protrusion proximate the aperture , the protrusion extending a distance from the facepiece exterior surface and including: an apex at which the protrusion extends a maximum distance from the facepiece exterior surface ; a latch activation region that includes the apex and extends in either direction from the apex ; and; an aperture ; and a protrusion proximate the aperture , the protrusion extending a distance from the facepiece exterior surface and including: an apex at which the protrusion extends a maximum distance from the facepiece exterior surface ; a latch activation region that includes the apex and extends in either direction from the apex ; and; an apex at which the protrusion extends a maximum distance from the facepiece exterior surface ; a latch activation region that includes the apex and extends in either direction from the apex ; and; a regulator being sized and configured to be received within the facepiece aperture, the regulator including: a regulator body having a facepiece engagement region matably engageable with the regulator engagement region ; a fluid flow path within the regulator body; and a latch within the regulator body , the latch being engaged and actuated by contact with the latch activation region to obstruct the fluid flow path), the regulator being rotatable within the facepiece aperture between a first rotational position and a second rotational position such that rotation of the regulator within the facepiece aperture from the second rotational position to the first rotational position engages the protrusion with the latch and actuates the latch to obstruct the fluid flow path. a regulator body having a facepiece engagement region matably engageable with the regulator engagement region ; a fluid flow path within the regulator body; and a latch within the regulator body , the latch being engaged and actuated by contact with the latch activation region to obstruct the fluid flow path), the regulator being rotatable within the facepiece aperture between a first rotational position and a second rotational position such that rotation of the regulator within the facepiece aperture from the second rotational position to the first rotational position engages the protrusion with the latch and actuates the latch to obstruct the fluid flow path. <EOS>