Precise and reliable: The pH meter and TDS EC meter are equipped with reliable automatic temperature compensation (ATC) to ensure accurate readings at different temperatures. To achieve high accuracy, the pH tester has a sensitive electrode sensor, measuring range: 0.00-14.00pH, Accuracy: 0.01pH. TDS meter is equipped with high quality titanium alloy probe, measuring range: 0-9990 ppm, accuracy: 2%. 4 in 1 Set: Professional pH Meter, TDS Meter, EC Meter and Temperature Meter 4 in 1 Set. You can know the water quality in seconds. With calibration function to ensure measurement accuracy. LCD display: Portable pH meters and digital TDS meters are equipped with a backlit display that allows you to read water quality results more accurately. It is easy to use even in dark environments. Both have an auto-shutoff feature to extend battery life. Wide Applications: The water quality tester is suitable for multiple occasions, such as drinking water, wine, juice, aquariums, hydroponics, spas, swimming pools and other water systems to ensure the safety of the water of your daily life. Scope of delivery: 3 pieces (PH meter + TDS/EC water quality detector + test paper)