PH Meter and TDS Meter, respectively adopt low impedance sensitive bulb and agile titanium alloy electrode respectively. Remove the protective cover, press the switch button, immerse the probe of the pH Meter/TDS Meter in the solution, and you can get the reading immediately. The digital pH tester has automatic temperature compensation function and Automatic Calibration function, make the measurement data not affected by the water temperature, and easy to calibrate. The Digital TDS & EC Tester has automatic temperature compensation function, Auto-off and Hold Function. The digital water tester shuts off automatically after 2 minutes of non-use to conserve batteries. Features a hold function that saves measurements for convenient reading and recording. The and portable size of the water meter allows you to easily carry it with you, and measure it anytime, anywhere. Test the purity of drinking water to it's healthy, monitor if Reverse Osmosis ()/DI System works properly, whether filter need replaced, maintenance aquarium, hydroponics(test nutrients) and pool etc. It is very suitable for scientific experiments in children's schools, testing different bottled water. Package Contents: 1 x pH meter, 1 x TDS & EC Meter, 3 x pH buffer powder, 2 x 1.5V LR44 battery (built-in), 1 x CR2032 battery (built-in). Colour:As Shown Material:Plastic Package Contents: 1set * digital ph meter 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.