... , Automatic Refractometer, Abbe Refractometer, PH/DDS/TDS Meter, etc.220/221 SeriesPortable pH/mV/ORP/oC/oF MeterThis Series meters includes ... the electrode is displayed before the meter returns to measurement mode. Per the slope value, you decides whether to change the pH electrode.Automatic Temperature Compensation:Using the ... useDimensions185(L)x88(W)x32(H)Weight300g Portable pH/mV/ORP/oC/oF Meter