ORP (Oxidation-reduction potential) digital water tester accurately and quickly measures organic matter in water with high precision and reliability. Fast response time ensures efficient testing. Ideal for various applications including 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. The device features a high-sensitivity electrode probe with a removable design to prevent damage and allow easy replacement. Equipped with IP67 rating, suitable for brief immersion. Includes 18-month warranty and lifetime customer support. When powered on in air, readings may fluctuate normally. Always replace the protective cap after use to prevent 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 data, press and hold the "MODE" and "HOLD" buttons simultaneously for 3 seconds to reset to factory settings. Reference ORP values: Hydrogen drinking water: -150mV to -400mV Normal drinking water: +150mV to +550mV Freshwater fish tank: 230-260mV Seawater fish tank: 350-450mV 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 test solution up to the marked immersion line. 4. Stir gently and wait for the reading to stabilize. 5. For temperature measurement, press and hold the "TEMP/HOLD" button. 6. After use, rinse the electrode with distilled water, turn off the device, and securely replace the protective cap. Technical specifications: 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: 32.18–140 °F Resolution: 0.1 °F Accuracy: ±0.5 °F Factory calibrated Power supply: 4 × 1.5V batteries Material: ABS plastic Color: Red Package includes: 1 × Hydrogen water tester Note: Light reflection and display differences may cause slight variations in color between the product image and actual item. Measurement error allowance: ±1–3 cm.