Widely used in domestic water, hydrogen- 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. ORP(Oxidation-reduction potential) digital water tester can accurately and quickly check the organic matter in water, which is extremely accurate and reliable, response; Hydrogen drinking water: -150mV and -400mV; drinking water:+150-550mV; Freshwater Fish Tank: 230-260mV; Seawater Fish Tank: 350-450mV. When the meter is on in the air, the value will be change in ; 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 ; 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., Weight: 0.37037660016 Pounds, Manufacturer: Lwaviwer