Apparatus and instruments for conveying, distributing, transforming, storing, regulating or controlling electric current; apparatus for recording, transmission or reproduction of sound or images; optical fibers; fiber-optic couplings; junction sleeves for fiber optics; fiber-optic connectors; protective sheaths for fiber-optic cables; light conducting filaments; fibre-optic periscopes; fiber-optic cables; electric wires and cables; electric cables with mineral insulation; electric cable conne...