This part of International Standard IEC 746 is applicable to analyzers, sensor units and electronic units used for the determination of oxidation reduction or redox potential values of aqueous solutions using relatively inert electron conducting electrodes. IEC 746-1 includes further definition of the scope and provides for the general aspects of all electrochemical analyzers including oxidation-reduction potential analyzers. The terms oxidation reduction potential and redox potential may be used interchangeably. Its object is to specify the terminology, definitions, requirements for statements by manufacturers and performance tests for analyzers, sensor units and electronic units used for the determination of the redox potential of aqueous solutions.