telephone earphone
7.105 telephone earphone. Earphone designed for use in a telephone set.
supra-aural earphone
7.104 supra-aural earphone. Earphone applied externally to the outer ear.
circumaural earphone
7.103 circumaural earphone. Earphone having a cavity large enough to cover the region of the head including and surrounding the pinna.
horn throat
7.102 horn throat. End of a horn where the cross-sectional area is smallest.
horn mouth
7.101 horn mouth. End of a horn where the cross-sectional area is largest.