【4-in-1】: This tester kit can help you test pH, water quality, temperature and EC in 5 seconds, to ensure that you always drink pure water. And these 2-in-1 pH Meter & TDS Meter are also ideal for home or laboratory testing. 【Accurate and Reliable】: pH meter: The measuring range is 0.00 - 14.00pH; The resolution is 0.01 pH; The accuracy is ±0.01 pH. TDS meter: The measuring range is 0-9999ppm; The accuracy is ±2% FS 【Automatic Calibration】: The pH Tester automatically calibrates at three points (calibration only at 6.86 points: accuracy at 0.1 pH). You don't need any tools; Simply remove the protective cover and immerse the pH meter electrode in the solution. Press "ON/OFF" to open the electronic pH meter, stir it lightly, and wait a few seconds until the readings are stable. 【LCD Backlight】: The pH meter and TDS meter adopt LCD backlight to make the data display clearer. Even if in a dark environment, you can easily view the data. When not in use, it will automatically turn off after