The digital redox point (ORP) sensor is an instrument used to measure the redox potential in aqueous solution, a parameter that reflects the relative strength of the oxidant and the reductant in the solution, lt usually consists of a working electrode (such as a platinum or gold electrode) and a reference electrode (such as a silver/silver chloride electrode). The working electrode is in contact with the solution, and the potential difference of the redox reaction occuring on the electrode is measured.