MEASUREMENT APPARATUS, NAMELY, REDOX ELECTRODES, PH ELECTRODES, REDOX SENSORS, PH SENSORS, ELECTROCHEMICAL SENSORS, POTENTIOMETRIC SENSORS; ELECTRODES; ULTRASONIC SENSORS; SENSORS FOR MEASURING PH OF WATER AND WASTE WATER, SENSORS FOR MEASURING THE PH OF PROCESS MEDIA, SENSORS FOR MEASURING THE INTERNAL CHEMISTRY OF AQUEOUS SOLUTIONS, NOT FOR MEDICAL USE; MEASURING EQUIPMENT, NAMELY, REDOX AND PH ELECTRODES; REPLACEMENT PARTS, FITTINGS AND ACCESSORIES FOR THE AFORESAID GOODS, NAMELY, REDOX EL...