21 ELECTRICAL APPARATUS-NAMELY, AMPLIFIERS; RADIO RECEIVERS; PHONOGRAPHS AND PUBLIC ADDRESS SYSTEMS; MICROPHONES; SPEAKERS AND CABINETS THEREFOR; TURNTABLES AND RECORD CHANGERS; TONE GENERATORS; TRANSFORMERS; IMPEDANCE NETWORKS AND THEIR CONTROLS; REMOTE CONTROL UNITS FOR MICROPHONES, AMPLIFIERS, AND PHONOGRAPHS; CABINETS FOR AMPLIFIERS, RADIO RECEIVERS, SPEAKERS, AND CONTROLS THEREFOR; PANELS COOPERABLE WITH THE CABINETS FOR MOUNTING SPEAKERS, AMPLIFIERS, RADIO RECEIVERS, PHONOGRAPHS, AND KEY LEVERS; PORTABLE PHONOGRAPHS AND PORTABLE PUBLIC ADDRESS SYSTEMS