For measuring pH, mV, oxidation-reduction potential (ORP), conductivity, resistivity in liquids

pHmeter-Thermometer, measurement of pH, mV and temperature.
Conductivity meter-Thermometer, measurement of conductivity, resistivity in liquids, total dissolved solids and temperature.
Dissolved oxygen meter: measures the concentration of dissolved oxygen in liquids (in mg/l), saturation index (in %) and temperature.

Electrodes, calibration solutions and temperature probes must be ordered separately.