Item Type: ORP TesterMaterial: ABSWeight: Approx. 190g/6.7ozMeasuring Range: 0~1999mg/LmVResolution: 1mVAccuracy: 5mVWorking Voltage: 4 x 1.5V (160mAh LR44 Battery) Battery Size: Approx. 11.6 x 5.4mm/0.5 x 0.2in (Battery Not Included)Working Temperature: 0-50Calibration: 1 Point CalibrationOperating Steps:1. Remove the protective cover.2. Tap the ON/OFF switch to turn on the power.3. Put the electrode into the test solution, shake it gently, and read the displayed value after the displayed value is stable.4. Touch the HOLD key to keep the currently measured value. If you need to re-measure, press the HOLD key again to automatically release the hold state.5. After use, press the switch, clean the electrode with distilled water, and put on the protective cover.Battery installation:If the display is fuzzy or not displayed, replace the battery in time. When replacing the battery, unscrew the upper cover to replace it. Pay attention to the polarity of the battery.Note:1: White crystalline salt appears around the electrode. This is a normal situation of ORP electrode. It can be dissolved and disappeared only by immersing the electrode in clean water.2: When testing the ORP value, it usually takes a few minutes to about 10 minutes. Wait for the value stabilizing and jumping very slowly or reading the measured value when it jumps up and down.3: The display values in ORP and the air are jumping randomly, it is normal situationthat there is no regular change4: After use, please turn off the power, clean the electrode with pure water or distilled water, use a soft tissue to absorb the water and put on a protective cover.