1.packing list:1 factory calibrated professional high precision pH pen +1 TDS&EC and temperature three-in-one water quality test pen +1 TDS portable test pen 2.PH resolution is 0.01pH, accuracy is ±0.01pH, measuring range is 0-14PH. TDS instruments range from 0 to 9990ppm, conductivity range from 0 to 9990 us/cm, temperature range from 0 to 60 °C /40°F to 132°F(Note: This meter can't test sea water) 3.The pH tester, equipped with automatic temperature compensation, adjusts to the water temperature and provides pH readings almost instantaneously. There is no requirement to manually account for the temperature of the test solution 4.For pH testers, simply place the instrument in the standard buffer, the CAL button, and it automatically start calibrating the data, for the water quality tester, the "HOLD"key to hold the reading, the "SHIFT" key once for TDS and EC conversion, and the "SHIFT"key twice for "°C /°F"conversion (do not worry if the description is not clear enough, please do not worry. Each product comes with the product manual, please read it carefully) 5.Often used for drinking water, domestic water, pool water, aquarium, spa, experiment to detect the ph value of water, hydroponics pH balance. Color: As Shown Material: plastic Package Contents: 1set x ph tester Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.