ORP (Oxidation-reduction potential) digital water tester accurately and quickly measures organic matter in water with high reliability and fast response. Suitable for testing hydrogen drinking water: -150mV to -400mV; normal drinking water: +150mV to +550mV; freshwater fish tanks: 230-260mV; seawater fish tanks: 350-450mV. Widely used for domestic water, hydrogen-rich water bottles, aquaculture, fish tank water quality monitoring, marine and freshwater systems, plant cultivation, laboratory testing, ecological research, and swimming pools. Features a high-sensitivity electrode probe with removable design to prevent damage and allow easy replacement. Plug-in structure enables user-friendly maintenance. IP67 rated for short-term immersion during hydrogen testing. Backed by 18-month support and lifetime customer service. When powered on in air, readings may fluctuate normally. Always replace the protective cap after use to avoid prolonged exposure of the electrode to dry air, which may lead to slow or unstable readings. If the electrode dries out, store it in distilled water to maintain performance. In case of abnormal readings, press and hold the "MODE" and "HOLD" buttons simultaneously for 3 seconds to reset to factory settings. Instructions for using the 3-in-1 H2/ORP/TEMP meter: 1. Gently remove the protective cap. 2. Press the "ON/OFF" button to turn on the device. 3. Immerse the electrode in the sample solution up to the marked immersion line. 4. Stir gently and wait for the reading to stabilize. 5. To measure temperature, press and hold the "TEMP/HOLD" button. 6. After use, rinse the electrode with distilled water, turn off the device, and replace the protective cap. Technical Parameters: H2 measurement range: 0–2400 ppb (0.001–2.4 ppm) Resolution: 1 ppb, 0.001 ppm Accuracy: ±2% ORP measurement range: -1200 to +1200 mV Resolution: 5 mV Accuracy: ±10 mV Temperature measurement range: 32.18°F to 140°F Resolution: 0.1°F Accuracy: ±0.1°F Factory calibrated Power supply: 4 × 1.5V batteries Material: ABS Color: Red Package Contents: 1 × Hydrogen water tester Note: Lighting and display differences may cause slight variations between the product color in images and actual item. Measurement tolerances may vary within ±1–3 cm.