leads to the clumsy telephonic communication technique described hereinbefore the current designs of the front voicemitter 6 itself have been shown to pose substantial intelligibility problems modified rhyme tests indicate that scores of 75 are typical for the m 40 series whereas experts for example human engineering labs have determined that a score of 91 is the minimum needed for adequate communications the m 42 version which has the microphone in the nose cup has adequate intelligibility however the microphone 17 itself poses a problem in that it is too large a smaller technically advanced unit would eliminate the need for the excessive dead space required in the nose cup to fit the microphone this dead space tends to lower the intelligibility of face to face communication and causes compatibility problems with weapons systems located below the center voicemitter in the chin area is an air outlet valve arrangement 6 fig1 c provided with an outlet valve cover 7 the face piece 1a 1b is provided in the eye area 10 with a pair of primary lenses 18 typically made of clear glass or plastic and each having an eye ring 19 the mask is additionally provided with a pair of demountable outserts or caps 20 for covering the primary lenses 18 each outsert 20 is seated in a soft rubber ring 21 that fits over the face piece eye rings 19 the rim of the rubber rings 21 fits snugly behind the respective eye rings 19 to protect the eyeglasses from scratches neutral gray outserts are typically used to reduce sun glare the outserts 20 also tend to reduce fogging the.