Electric, electronic and optical measuring, signalling and checking (supervision) apparatus and instruments, included in this class, namely electric electroacoustics apparatus and instruments and parts therefor; apparatus and instruments for recording, transmission and reproduction of audio signals and parts thereof, included in this class; apparatus for recording and reproduction of electrical signals, in particular audio signals; apparatus for wireless transmission of acoustic information; apparatus for sending, transmitting and receiving audio or video signals, in particular high-frequency sound transmitters and sound transmission technology apparatus; pocket transmitters and receivers, in particular pocket transmitters and receivers in the uhf and vhf range, and parts therefor; diversity receivers; small earphones; aerials; narrow-band system and broadband system apparatus for use in sound transmission technology; transmitters, in particular multi-channel transmitters, single-channel transmitters, infrared transmitters, RF transmitters; receivers, in particular multi-channel, single-channel and dual-channel receivers, infrared receivers and radio receivers, headphone receivers, stethoset receivers and parts for the aforesaid goods, included in this class; apparatus for sound transmission and reproduction apparatus; headsets; conference installations, consisting of microphone units, loudspeakers, microphones, monitors and telephones; devices for the analogue and digital transmission of audio and video and data signals; software for the aforesaid control, tuning and checking systems; data carriers equipped with programs; software, in particular on CD-roms, DVDs, hard drives, floppy disks and volatile and non-volatile memories; conference and telecommunications technology apparatus and instruments; microphones, in particular dynamic microphones, condenser microphones, electric microphones, headset microphones, gooseneck microphones, line microphones, wireless microphones, lapel microphones, microphones with integrated transmitters, in particular condenser microphones with built-in high-frequency transmitters, microphone modules, pressure microphones, switchable microphones, microphone capsules and parts for the aforesaid goods, included in this class; microphone isolating distributors; apparatus for broadcasting sound, data or images; repeating coils; microphone cases; electroacoustic transducers, in particular headphones, dynamic headphones, electrostatic headphones, wireless headphones, headphones for use in vehicles and aeroplanes, in particular having infrared or radio transmission, headphones having active noise compensation, loudspeakers, including wireless loudspeakers; parts and accessories for electroacoustic converters and headphones, namely ear pads, volume controllers, repeaters, battery plugs, plug-in chargers, handset cords; electro-acoustic and visual identifiable guide systems, including multi-lingual guide systems, consisting of transmitters, receivers, in particular sound signal receivers and headphones; apps (software) for controlling sound recording and reproduction apparatus; apps (software) for recording and reproduction of audio signals; conference phones.