Features: All adopt sensitive probes, which can quickly and accurately read, effectively helping you determine the pH value of water or solution and detect impurities in it. In order to achieve high accuracy, the pH measuring instrument is equipped with flexible glass probes, and the TDS measuring instrument is equipped with alloy probes. You do not need to worry about the temperature of the solution affecting the measurement results, as both pH and TDS meter have automatic temperature compensation functions that can be adjusted according to the water temperature. Handheld to complete the detection, press the button, and the PH and TDS water quality testers will tell you the overall water puritying level of the liquid. As tools for improve life quality, they can be used to test pH balance and water quality in drinking water, swimming pools, aquariums, reverse system, hydrotherapy or hydroponics. It can be easily placed in your pocket. Specifications: PH Meter Detection Range: 0-14PH Resolution: 0.01PH Accuracy: 0.1PH Working Temperature: 0~60 Size: 149x25.5x15mm/5.87x1.00x0.59in TDS Meter Measurement Range: 0~99990ppm Measurement error: 2% Temperature Measurement Range: 0-99 (32-212 ) Size: 150x26x15mm/5.91x1.02x0.59in Note: After the TDS meter penetrates into the solution to be test, it needs to be stirred to avoid bubbling. When the pH meter is opened in air, the value will jump irregularly due to the sensitive glass probes, which is normal. The values in the air cannot be used as a reference. It is recommended to calibrate before use. Once calibrated, it can be reused for ten days. Please read carefully and calibrate according to the calibration methods in the manual. Package includes: 1x PH meter 1x TDS meter 2x 3V CR2032 Button Battery 3x PH Meter Calibration Powder(PH6.86, PH9.18, PH4) 1x User Manual