Specification: TDS: Short for total dissolved solids Range: 0-9990ppm Accuracy: +/- 2% Temperature range: 0-50 Celsius Degree (32-122F) Size: 155mm x 31mm x 21mm Power Input : 2 x 1.5V Button Cell Battery Package include: 1 X TDS Testing Pen 1X Manual Feature: 1, Shuts off automatically after 10 minutes of non-use. 2, Automatic temperature compensation function: it can automatically change the displayed value into the value of 25 Celsius Degree. 3, High accuracy: Use the Titanium alloy probe which can avoid magnetic disturbance to test water and only has the error ( 0.1). 4, Measuring temperature: 0-50 ℃ and it can be stored in the environment (- 30 ℃ ). 6, LCD display screen: Big LCD display screen which has great waterproof performance and let you easily read the displayed value. 7, Fast measuring: can measure once in five seconds. 8, Dual Range: Measures form 0-999ppm, with a resolution of 1ppm. From 1,000 to 9,990ppm, the resolution is 10ppm, indicated by drinking x 10image, multiply the reading by 10. Important Note: 1, Do not drop the entire TDS meter in water of dip beyond the maximum immersion level. 2, The TDS-3 tester cannot test the water with high temperature such as, boiled water. 3, The TDS-3 tester cannot be applied to test the flowing water.