【5-in-1 Function】This is a water testing kit with pH tester, TDS meter, and EC salinity temperature test function. The backlit LCD display makes it easy to read the displayed values. 【Easy to Use】Press the power button to turn on. Press "HOLD" to lock the value, long press "HOLD" to change the temperature unit. Press "MODE" to switch between functions. 【Absolute Accuracy】The pH resolution is 0.01 pH, the accuracy is ±0.05 pH. TDS meter resolution 1 ppm 0.1 ppt, accuracy ±2%. Conductivity resolution 1 uS/cm 0.1 mS/cm, accuracy ±2%. Thermometer resolution 0.1 ℃/℉, accuracy ±0.5 ℃. Salinity resolution 0.01%, accuracy 0.01-5.00% (±0.1%) 5.10-25.00% (±1%). 【Versatile Application】Ideal for home or laboratory use. Suitable for testing the pH of drinking water, swimming pools, aquariums, reverse osmosis systems, spas, or hydroponics. 【Robust and Durable】This pool tester is IP67 waterproof, so it can continue to be used even if it is dropped into the aquarium. Please do not use this pH meter