Item Type: ORP169F Meter Pen Material: Plastic Measurement Range: 0 - 1999 mg/L mV Resolution: 1 mV Accuracy: ±5 mV Operating Temperature: 0 - 50 °C Battery: 4 x 1.5V (AAA) included Waterproof: Yes Dimensions: 188 mm x 35 mm x 35 mm Color: As shown Material: ABS Operation: 1. Remove the protective cap. 2. Clean the electrode with distilled water and gently dry with filter paper. 3. Press the OFF/ON button to power the device. 4. Immerse the meter electrode into the solution up to the immersion level. Do not immerse above the display level. 5. Stir gently and wait for the reading to stabilize. 6. After use, turn off the device, rinse the electrode with distilled water, and replace the protective cap. Package Contents: 1 x ORP169F Meter Pen Note: Light reflection and different displays may cause slight variations in the color of the item shown in the picture compared to the actual product. Measurement error allowance is +/- 1-3 cm.