Digital Tester 169E ORP/Redox Tester, ORP Meter for Measuring Oxidation-Reduction Potential, High Precision Potential Meter with Positive and Negative Measurement Oxidation-Reduction Potential (ORP) represents the oxidation potential of a solution. The ORP value measures the redox capacity of a solution in millivolts (mV). This ORP meter is specialized equipment for testing the redox potential of solutions. The instrument features a waterproof enclosure with an IP55 rating. The electrode is replaceable. Includes a data hold function for convenient measurement reading and recording. Designed as a compact negative potential (O.R.P) tester. Incorporates advanced technology and components to reduce size and cost while maintaining quality, making it widely used for applications such as functional water purifiers and negative ion energy cups requiring negative potential measurement. Main Technical Specifications: - Measurement Range: 0 to ±1999 mV - Resolution: 1 mV - Accuracy: ±5 mV - Battery: 4 x 1.5V (not included) - Operating Temperature: 0°C to 50°C - Calibration: Single-point calibration Instructions: 1. Remove the protective cover. 2. Press the "ON/OFF" button to power on the device. 3. Immerse the electrode into the test solution and gently shake until the display stabilizes. 4. Press the "HOLD" button to lock the current reading. To resume measuring, press "HOLD" again to release the hold function. 5. After use, turn off the device, rinse the electrode with distilled water, and replace the protective cover. Battery Replacement: If the display becomes dim or unclear, replace the batteries. Unscrew the battery compartment cover, insert new batteries observing correct polarity, and secure the cover. Calibration Procedure: 1. Soak the electrode in distilled water for several hours before first use. 2. Immerse the electrode in standard calibration solution and stir gently. 3. Adjust the calibration trimmer with a screwdriver until the LCD displays 265 mV. 4. Rinse the electrode with distilled water and blot dry with filter paper. Color: White + Green Material: ABS + Electronic Components Dimensions: 18.8 cm x 3.5 cm x 3.5 cm Package Contents: - 1 x 169E ORP Tester - 1 x English Manual Note: Lighting and monitor differences may cause slight color variations between the product image and actual item. Measurement error tolerance is ±1–3 cm.