Waterproof -Low Power Consumption -Automatice Switch-off -Low-battery Alarm (as long as there is any display the accuracy is guaranteed) Model: ZDS-EC ZDS-TDS ZDS-uS/cm ZDS-mS/cm ZDS-ppm ZDS-ppt Measuring Range: 0-19.99 EC 0-1999 mg/l 0-1999 uS/cm 0-19.99 mS/cm 0-1999 ppm 0-10.00 ppt Resolution: 0.01 EC 1 mg/l 1 uS/cm 0.01 mS/cm 1 ppm 0.01 ppt Accuracy +/-2% FS Temp 5 - 50癈 (ATC) Size 150 x 32 x 20 mm