Pen Type ORP/REDOX Tester with Digital LCD Display Redox Meter Professional ORP Water Quality Detector Oxidation Reduction Potential Monitor Analyzer The ORP meter is a professional tool for testing ORP of your water level. Very easy e, just turn on it and immerse the electrode in the solution to be tested, then stir gently and wait for the reading to stabilize. It will provide you the most accurate and stable reading. Features: Designed to test the Oxidation Reduction Potential(ORP) value of water. High accurate, easy e and it will provide instant display of results. Clear LCD display screen for easy reading data. With data hold function to facilitate the recording of measurement data. Pen-type design, compact and portable size, easy to carry. IP55 waterproof design, and the electrode is replaceable. Powered by 4*1.5V(AG-13) button cell battery(not included). Widely apply in water sources, aquarium, hydroponics, swimming pools, water purification systems, etc.  Specifications: Model: ORP-169E  Measuring Range: -1999～1999mV Resolution: 1mV Accuracy: ±5mV Battery: 4*1.5V(AG-13) Button Cell Battery (Not Included) Waterproof level: IP55 Standard Operating Temperature: 0℃～50℃ Item Size: 188 * 35 * 35mm / 7.40 * 1.38 * 1.38in Package Size: 195 * 90 * 45mm / 7.68 * 3.54 * 1.77in Package Weight: 295g / 10.41ounce Package List: 1 * ORP Meter  1 * Mini Screwdriver 1 * User Manual(English)