Measuring and testing apparatus and plants built thereof for use in producing pipes, wires, bands, steel rods, billets, rails and sections, namely, scales, ammeters, wattmeters, thermometers, water analyzers, gas and air analyzers, automatic chemical analyzers, speed measuring apparatuses, namely, speedometers and speed indicators, pressure measuring apparatuses, namely, pressure gauges, pressure detectors, and pressure indicators, angle gauges, distance meters, roughness gauges, strip flatne...