4 in 1 pH MeterA very complete kit for checking the quality of your water, whether it's from a faucet, hot tub, homebrew, indoor soil growing, aquarium, hydroponics or swimming pool. In addition, TDS tester and PH tester as pens are small in size, light in weight, and easy to carry when going out! High AccuracyPH meters range from 0.00-14.00 (PH), while digital EC and TDS meters range from 0 to 9999 ppm. PH resolution is 0.01pH, accuracy 0.01pH. TDS: 0 - 9999ppm, conductivity: 0 - 9999us/cm, accuracy: 2%, LCD blue backlight display for reliable and fast readings. Easy CalibrationPH tester automatically calibrates at three points). You don't need any tools; just remove the protective cap and dip the pH meter electrode into the solution. Press "ON/OFF" to turn on the electronic pH meter, stir gently, and wait a few seconds until the reading stabilizes. Quick To UseWhen you press the "HOLD" button, the TDS water tester will lock the measurement and automatically shut down after a few minutes of inactivity. The pH tester has an auto-calibration feature so you can get a reading quickly! Wide ApplicationSuitable for home and laboratory pH testing, including drinking water, plating baths, aquarium water, swimming pool water, well water, deep diving, aquaculture, food processing, and more.