TANNOY

[ ELECTRIC SIGNALLING AND ALARM APPARATUS AND PARTS THEREOF, FOR USE IN FIRE, BURGLAR, AIR RAID AND SIMILAR ALARM SYSTEMS, EMPLOYING EITHER VISUAL OR AUDIBLE SIGNALS; TELEPHONE SYSTEMS AND APPARATUS, AND PARTS THEREOF; TRANSMITTING AND RECEIVING TELEPHONE AND RADIO APPARATUS, AND PARTS THEREOF; ] ELECTRIC PUBLIC ADDRESS AMPLIFYING AND REPRODUCING APPARATUS, INCLUDING ELECTRIC AMPLIFIERS, [ MICROPHONES, ] LOUDSPEAKERS, [ GRAMOPHONE PICK-UPS AND ELECTRIC SWITCHES; PHOTOELECTRIC APPARATUS COMPRISING PHOTOELECTRIC CELLS, RELAYS AND LIKE ACCESSORIES; ELECTRIC OSCILLATION GENERATORS; ELECTRICALLY OOPERATED SOUND GENERATORS-NAMELY, ELECTRIC BELLS, BUZZERS AND SIRENS, AND AUDIO-FREQUENCY ELECTRIC OSCILLATORS; AND ELECTRICAL ] SOUND [ RECORDING, REPRODUCING AND ] AMPLIFYING INSTRUMENTS AND APPARATUS [ EXCLUSIVE FOR SO-CALLED SOUND FILM APPARATUS ]