Physical, electric, electronic and electrochemical measuring, control, security, monitoring, regulating, indicator and switching devices, apparatus and instruments as well as parts thereof; electric and electronic measuring transducers, amplifiers, transformers, disconnectors, isolation amplifiers, electronic power supplies, signal duplicators; calibrating devices, apparatus and instruments; process analyzers in the nature of measuring apparatus; process sensors; pH sensors; redox sensors; conductivity sensors; oxygen sensors; measuring apparatus for use in measuring pH, redox, conductivity, oxygen, clouding and TOC, and fittings therefor; calibrating and testing apparatus for calibrating and/or testing all of the aforementioned goods as well as parts thereof; data processing apparatus, systems and programs for operating, configuring and calibrating the aforementioned goods; digital indicators; scientific, industrial and laboratory installations consisting of the aforementioned goods