【5-in-1 Function】 This is a water testing kit with a pH tester, TDS meter, and EC salinity/temperature tester. The backlit LCD screen makes it easy to read the displayed values. 【Easy to Use】 Press the power button to turn on. Press "HOLD" to lock the value, press and hold "HOLD" to change the temperature unit. Press "MODE" to switch between the different functions. 【Absolute Accuracy】 pH resolution is 0.01 pH, accuracy ±0.05 pH. TDS meter resolution is 1 ppm (0.1 ppt), accuracy ±2%. Conductivity resolution is 1 µS/cm (0.1 mS/cm), accuracy ±2%. Thermometer resolution is 0.1°C/°F, accuracy ±0.5°C. Salinity resolution 0.01%, accuracy 0.01-5.00% (±0.1%), 5.10-25.00% (±1%) 【Wide Application】 Ideal for home or laboratory use. Suitable for testing the pH balance of drinking water, swimming pools, aquariums, RO systems, spas, or hydroponic systems. 【Robust and Durable】 This pool tester is IP67 waterproof, so it can continue to be used even if it falls into the aquarium. Please try to avoid