ORP(Oxidation-reduction potential) digital water tester can accurately and quickly check the organic matter in water, which is extremely accurate and reliable, quick response; Hydrogen drinking water: -150mV and -400mV; Normal drinking water:+150-550mV; Freshwater Fish Tank: 230-260mV; Seawater Fish Tank: 350-450mV. Widely used in domestic water, hydrogen-rich bottle, aquaculture, fish tank water quality, marine aquaculture, freshwater aquaculture, flower and plant cultivation, laboratory testing, ecological research and swimming pool, etc. The probe uses high-sensitivity electrodes; The probe is removable to prevent accidental damage, and the plug-in design makes it easy to replace the probe by yourself; IP67 rating, brief Hydrogen test pen immersion. 18 month and friendly customer service. When the meter is on in the air, the value will be change in normal; When using the test pen, please cover the protective cap in time to avoid the test electrode being exposed to dry air for a long time, which may cause slow or unstable data reading; If the electrode is dry, keep the electrode moist in distilled water; When the data is abnormal, press and hold the "MODE" button and "HOLD" button at the same time for 3 seconds to restore the factory settings. Hydrogen drinking water: -150mV and -400mV; Normal drinking water:+150-550mV; Freshwater Fish Tank: 230-260mV; Seawater Fish Tank: 350-450mV. How to use 3 in 1 H2/ORP/TEMP Meter? 1. Remove the protective cap gently; 2. Turn the meter on by pressing the "ON/OFF" button; 3. Immerse the meter electrode in the test solution (immersion depth can not be over the immersion line); 4. Stir gently and wait until the reading stabilized; 5. If you need test temp, please press "TEMP/HOLD" button longly to get the reading; 6. After finished use, clean the electrode with distilled water. and turn off the meter, and close the protective cap. Tecnical Parameters: H2 measurement range: 0 - 2400ppb (0.001-2.4ppm); Resolution: 1ppb, 0.001ppm; Accuracy: 2%, reliable and quick readings; ORP Measurement Range: -1200-+1200mV; Resolution: 5mV; Accuracy: 10mV; TEMP Measurement Range: 32.18-140F; Resolution: 33.8F; Accuracy: 32.18F; Factory calibrated; Voltage: 4*1.5V Material: ABS colour: red Package Contents: 1 x Hydrogen water bottle 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.