Scientific, photographic, cinematographic, optical, measuring, signaling and checking apparatus and instruments; apparatus and instruments for conducting, switching, transforming, accumulating, regulating and controlling electricity; apparatus for recording, transmission and reproduction of sound and images; magnetic data carriers; electromechanical and electronic components and apparatus, microphones, electronic amplifiers, electrical and electronic contact and connection elements, plug connections, connectors for electrical connection lines, connectors and connectors for optical fibers, loudspeaker plugs, electric power distribution blocks, electronic power supply units, power distribution and control apparatus, devices; power cable.