This is a digital TDS meter tester to test the filter water quality purity， to check the performance of your water filter， to check for hardness (1grain=17ppm)， to make sure you always drink pure water.Features:Saves measurements for convenient reading and recordingAuto-off function: turns off meter after 5 minutes of non-use to conserve batteriesAutomatic temperature compensationShift between TDS and ConductivityCan be used in : Water purifiers and filters， food(vegetable ， fruit)&drink quality monitoring， pools and spas， aquarium， hydroponicsMeasurement range: TDS: 0-9990 ppm Dearees Celsius: 0.1-80.0 Celsius， 32.0-176.0FahrenheitAccuracy: +/-2%Item Size: 155mm*30mm*15mmColor: White