Specification: Color:?White,?Blue. Type:White,?Blue,?LED White, LED Blue. Material: ABS, Plastic. Batteries Included: Yes. Measurement Accuracy: 0.1. PH Range: 0 to 12 pH. Widely Used for different type of water: Swimming pool, Aquarium, RO/DI system, Hydroponics, Drinking water, Tap water?. How to check your water purity? 1. Remove the protective cap and turn on the TDS& EC meter. 2. Put the TDS meter into the test water and immerse it up to the immersion line. 3. When the result shows steadily, press"HOLD" ?the and take it out of water. Press"SHIFT"to read different modes you ?want. 4. Wipe clean the electrode after using ee turnoff the TDS meter and close the protective cap. Package included: 1 x?Water Quality Tester