This combination, single-junction electrode contains a platinum ORP sensor, a glass pH sensing bulb, a replaceable junction, and refillable reference electrolyte solution. Once you’ve replaced this sensor on your Aqua TROLL 400 or smarTROLL Multiparameter Handheld, you’ll need to perform separate calibrations for pH and ORP.

 This sensor is for Aqua TROLL 400 probes and the smarTROLL Multiparameter Handheld.