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. Suitable for various applications including drinking water, hydrogen-rich water bottles, aquaculture, fish tanks, freshwater and marine environments, plant cultivation, laboratory testing, ecological research, and swimming pools. Typical ORP values: Hydrogen drinking water: -150mV to -400mV Normal drinking water: +150mV to +550mV Freshwater fish tank: 230-260mV Seawater fish tank: 350-450mV Features: - High-sensitivity electrode probe - Removable probe design for easy replacement and protection against damage - Plug-in structure allows user-replaceable probe - IP67 rated for water resistance; brief immersion allowed - Factory calibrated for accuracy - 18-month warranty with lifetime customer support Usage instructions: 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 replace the protective cap. To prevent inaccurate readings, avoid prolonged exposure of the electrode to dry air. If the electrode dries out, store it in distilled water to maintain moisture. If abnormal readings occur, press and hold the "MODE" and "HOLD" buttons simultaneously for 3 seconds to reset to factory settings. Technical specifications: - H2 measurement range: 0–2400 ppb (0.001–2.4 ppm) - H2 resolution: 1 ppb / 0.001 ppm - H2 accuracy: ±2% - ORP measurement range: -1200 to +1200 mV - ORP resolution: 5 mV - ORP accuracy: ±10 mV - Temperature measurement range: 32.18°F to 140°F - Temperature resolution: 0.1°F - Temperature accuracy: ±1°F - Power supply: 4 × 1.5V batteries (not included) - Material: ABS plastic - Color: Red Package contents: 1 × H2/ORP/TEMP meter Note: The actual product color may vary slightly due to lighting and display differences. Measurement error is within ±1–3 cm.