【4 in 1】A very complete kit to check the quality of your water, whether it comes from a faucet, a hot tub, a home brew, an indoor soil, an aquarium, a hydroponic culture or a swimming pool. In addition, the TDS tester and the PH tester as pens are small in size, light in weight and easy to carry when you go out. 【High precision】The pH meters range from 0.00 to 14.00 (PH), while the digital EC and TDS meters range from 0 to 9999 ppm. The PH resolution is 0.01 pH, the accuracy ± 0.01 pH. TDS: 0 - 9999ppm, Conductivity: 0 - 9999us/cm, Accuracy: ± 2%, Blue backlit LCD display for reliable and fast readings. 【EASY TO CALIBRATE】The pH tester is automatically calibrated at three points). You don't need any tools; just remove the protective cap and immerse the pH meter electrode in the solution. Press "ON/OFF" to turn on the electronic pH meter, stir gently and wait a few seconds until the reading stabilizes. 【EASY TO 【USE】When you press the "HOLD" button, the TDS water tester will lock the