Hill, Van Santen, Steadman & Simpson
Earphone
 An earphone having a housing, a speaker unit accommodated in the housing and a duct formed in the housing to pass sound emanated from the rear surface of the speaker unit and in which a mesh subjected to water repellent treatment is provided within the duct. 
Sony Corporation
H
H04R
inventional
Makoto Shingo Yoshiyuki
Yamagishi Watanabe Kamon