9 Scientific, surveying, optical, weighing, measuring, signalling, control and teaching apparatus and instruments, namely, [ video cameras, liquid crystal displays, light emitting diode displays, ] tape tension dinamometers, tape tensioning blades, tape flatner meters, thermometers, speedometers, pressure gauges, angle gauges, distance meters, roughness gauges, control devices, such as flatness control, roughness control, pressure control, tensioning control, control panels for rolling mills, electrical and magnetic detectors, frequency meters, apparatus for recording, transmission or reproduction of sound or images, namely, signal transmitter, blank magnetic data carriers, calculating machines; data processing equipment, namely, data processors, and computers, stored computer programs for controlling rolling mills