Milwaukee EC59 LED Waterproof Combination Pocket EC/TDS/Temp Tester with Replaceable Electrode, 3999 microSiemens/cm, 1 microSiemens/cm Resolution, 2 percent EC/TDS Accuracy, 0.0 to 60.0 degree C Portable, waterproof conductivity, total dissolved solids (TDS), and temperature meter Automatic temperature compensation, automatic one-point calibration Dual-level LCD screen displays both temperature and either conductivity or TDS Comes with the Mi59P probe, which is replaceable