ELECTRICAL, ELECTRONIC, OPTICAL, MEASURING, SIGNALING AND MONITORING APPARATUS, IN PARTICULAR, FOR RECEIVING, TRANSMITTING, AND REPRODUCING AUDIO SIGNALS, NAMELY, TRANSMITTERS AND RECEPTION DEVICES CONSISTING OF RF RECEIVERS, RF INPUT MODULES; ELECTRICAL APPARATUS IN ELECTROACOUSTICS AND PARTS THEREOF, NAMELY, DEVICES AND INSTRUMENTS FOR RECEIVING, TRANSMITTING AND REPRODUCING AUDIO SIGNALS AND ACOUSTIC INFORMATION, NAMELY, MICROPHONES, FILTERS FOR NOISE REDUCTION; BATTERY CHARGERS AND PARTS ...