Introduction: This digital meter is an ideal instrument for any aquarium, the fishing industry, swimming pools, school laboratories, food & beverage, etc. And, this Digital TDS Water Quality Tester is ideal for all basic water testing applications. This product is highly efficient and accurate due to its advanced microprocessor technology. Hold Function: stores measurements for convenient reading and recording. Auto-off function: the meter shuts off automatically after 10 minutes of non-use to conserve batteries. Measurement Ranges is between 0-9990 ppm, and from 0-999 ppm, the resolution is in increments of 1ppm; from 1000 to 9990 ppm, indicated by a blinking 'x10' image. Features: Measures total dissolved solids (TDS) and temperature Measurement Range: 0-9990 ppm, 0 degree-99 degree (only TDS-3), 32- 212 (only TDS-3) Accuracy: 2% Full Scale: ±1, ±2 Digital Calibration (push button): Factory Calibrated Shuts off automatically after 10 minutes of non-use Automatic temperature compensation function: it can automatically change the displayed value into the value of 25 High accuracy: Use the Titanium alloy probe which can avoid magnetic disturbance to test water and only has the error (± 0.1) Measuring temperature: 0 - 50 and it can be stored in the environment (- 30) LCD display screen: Big LCD display screen which has great waterproof performance and let you easily read the displayed value Fast measuring: can measure once in five seconds Specifications: Size: 14.5cm * 2.6cm * 2.0cm (TDS) Accuracy: ± 0.1PH (at 20) Battery: 4 x 1.5V (AG-13 button battery) Relative Humidity: <95 The using life of battery: 700 hours Working temperature: 0 - 50 Power source: 2 x 1.5 V (button cell) Zero: Adjust by the compensate potentiometer Note: The value of TDS can show the content of impurities. The bigger of the value means that the content of impurities is larger; conversely, the content of impurities is small.