AUDIOMETER, NOISE GENERATORS, ELECTRO-ACOUSTIC EARS, GROUP AUDIOMETERS, SOUND ANALYZERS AND ASSOCIATED AMPLIFIERS SOLD AS A SINGLE UNITS, ACOUSTIC CALIBRATORS, NOISE-ATTENUATING EARPHONE HOUSINGS, AND APPARATUS FOR TESTING HEARING

AUDIOMETER, NOISE GENERATOR, ELECTRO-ACOUSTIC EAR, GROUP AUDIOMETER, SOUND ANALYZER AND ASSOCIATED AMPLIFIER, ACOUSTIC CALIBRATOR, AND NOISE-ATTENUATING EARPHONE HOUSINGS