Reagecon's Redox Standards are not calibration standards; rather, they serve as control or reference material. This is because the sensing electrode doesn't need to be calibrated because Redox Oxidation/Reduction (ORP) is an absolute measurement.
These Standards regulate the way the measuring metre operates, the analyst's method, the reference and sensing electrodes, and the surrounding environment.
Buffer solutions redox
Redox buffer solutions
Solutions redox