You do not need to worry about the temperature of the solution affecting the measurement results, as both the pH and TDS meters have automatic temperature compensation functions that adjust according to the water temperature. All units feature sensitive probes that provide fast and accurate readings, helping you determine the pH or TDS value of water or other solutions and detect impurities. For accuracy, the pH meter is equipped with a glass probe, while the TDS meter uses an alloy probe. These handheld tools are suitable for testing water quality in drinking water, swimming pools, aquariums, reverse osmosis systems, hydrotherapy, and hydroponics. Compact and portable, they fit easily in your pocket. To perform a test, simply press the button—the pH and TDS meters will display the water purity level of the liquid. pH Meter Specifications: Detection Range: 0–14 pH Resolution: 0.01 pH Accuracy: ±0.1 pH Operating Temperature: 0–60°C Dimensions: 149 × 25.5 × 15 mm (5.87 × 1.00 × 0.59 in) TDS Meter Specifications: Measurement Range: 0–99990 ppm Measurement Error: ±2% Temperature Measurement Range: 0–99°C (32–212°F) Dimensions: 150 × 26 × 15 mm (5.91 × 1.02 × 0.59 in) Package Includes: 1 × pH meter 1 × TDS meter 2 × 3V CR2032 button batteries 3 × pH calibration powders (pH 4.00, pH 6.86, pH 9.18) Color: White Material: ABS Note: After immersing the TDS meter into the solution, gently stir to avoid air bubbles. When the pH meter is exposed to air, the reading may fluctuate due to the sensitivity of the glass probe—this is normal. Readings taken in air are not valid. The package includes only the items listed above. Note: Color variation may occur due to lighting conditions and screen settings. Dimensional tolerance: ±1–3 cm.