Loudspeakers; Megaphones; Microphones; Aerial amplifiers; Audio dubbing apparatus; Audio mixers; Audio mixing consoles; Audio speakers; Karaoke machines; Loudspeakers with built in amplifiers; Microphones for communication devices; Power amplifiers; Power controllers; Radio monitors for reproduction of sound and signals; Sound cards; Sound equalizers and crossovers; Speaker microphones; Wireless microphones with integrated speakers; Wireless transmitters and receivers