Scientific, nautical, surveying, photographic, cinematographic, optical, weighing, measuring, signaling, checking, supervision, life-saving and teaching apparatus and instruments, namely, electrical and electronic safeguards and protection devices and systems, namely, computer processing units, control modules, input/output modules, and electrical and electronic sensors, for use in influencing, monitoring or shutting down computer controlled procedural processes; electrical and electronic sensors and electrical and electronic devices for fluid or gas analysis, electrical and electronic sensors and devices for measuring or monitoring electrochemical variables, namely, electrolytic conductivity, pH value, substance concentration or redox potential; electrical and electronic sensors and electrical and electronic devices, namely, temperature probes, temperature sensors, thermocouples, temperature monitors, temperature limiters, thermometers, transmitters for temperature, humidity, pressure and electro-chemical quantities, pressure and vacuum gauges, pressure switches, level measurement probes, flow rate sensors, flow rate transducers, transducers for temperature and electro-chemical quantities, hygro and hygrothermo transducers, hydrostats and humidity transducers, for measuring or monitoring physical variables, namely, thermodynamic variables, temperature, pressure, force, distension, moisture, level and flow; electrical and electronic display devices, namely, display panels, thermostats, and mechanical and digital indicators, for optically displaying measured values of thermodynamic variables, namely, temperature, pressure, force, distension, moisture, level and flow, or electrochemical variables, namely, electrolytic conductivity, pH value, substance concentration or redox potential; electrical and electronic logging devices and recording devices, namely, electronic data recorders, for measured values of thermodynamic variables, namely, temperature, pressure, force, distension, moisture, level and flow, or electrochemical variables, namely, electrolytic conductivity, pH value, substance concentration or redox potential; apparatus and instruments for conducting, switching, transforming, accumulating, regulating or controlling electricity, namely, transmitters for electricity, thyristors, electric actuators, electric capacitors, electric relays, contact protection relays, transistor relays and semiconductor relays, printed circuits, assembled electronic circuit boards, electro-mechanical, electronic and microprocessor controllers, electric control panels, electric switches, electric time switches; apparatus for recording, transmission and reproduction of sound and images; data processing equipment, computers; computer software for controlling, regulating, parameterising and monitoring all aforesaid apparatus, instruments and devices