Feature: 1. The large LCD digital display with backlight can easily cope with various environments, and the values can be viewed accurately even in dark and strong light environments. 2. 99 data can be recorded manually, and the data record/compare/view can be reached by one button, which is convenient and worry‑free. 3. Upgrade the imported smart chip, which is more than 50% faster than the traditional old chip, the measurement is more accurate, and the response is more sensitive. 4. More comprehensive functions, with data storage, unit switching, automatic shutdown, temperature compensation, salinity compensation, altitude compensation, and automatic calibration functions. 5. The probe has an anti‑collision cap, an integrated button, and a streamlined body, which is easy to use. It is suitable for the fields of experimental scientific research, sewage treatment, domestic water, aquatic planting, aquaculture, and medicine. Specification: Item Type: Dissolved Oxygen Meter Material: ASBS Color: As shown in the picture Model: AR8406 Battery: 1.5V AAAx4 (not included) Application: Experimental scientific research, sewage treatment, domestic water, aquatic planting, aquaculture, medicine field Dissolved Oxygen Correction 100% saturated dissolved oxygen correction in the air Temperature Measurement Range -5.0~60.0℃ Temperature Resolution 0.1℃ Temperature Accuracy ±0.5℃ Temperature Unit Switch ℃/℉ Record Data Manually record 99 group Salinity Compensation 0~42ppt Altitude Compensation 0~3500m Temperature Compensation Automatic temperature compensation ATC Automatic Shut-Down Shut down after one hour of inactivity .SET button: Short press the switch and long press to enter the setting mode CAL/ESC key: long press in measurement mode to enter calibration mode setting mode, short press to exit setting mode Recall key: Short press to turn on or off the backlight/long press to view the saved data, press the up and down keys to view the recorded data one by one, and press the ESC key to exit the record viewing mode To view the record data, press the ESC key to exit the record viewing mode Mode/△ key: increase value/switch mode Save/▽ key: Decrease the value/switch mode/measurement mode short press to save the data manually (maximum 99 records) Enter key: confirm key Calibration Steps: 1: Press the SET button to turn on 2: When calibrating, you need to press the Mode key to switch in the percentage "%" mode. 3: In the air medium measured value stable well to ensure that there is no water droplets or mud at the platinum place 4: Long press the "CAL/ESC" key for more than 1 second to enter the calibration, wait for a few minutes to complete the calibration automatically or manually press the "Enter" key to complete the calibration. After the calibration is completed, it is normal to display 99%~101%. If the value exceeds this value, it needs to be re-calibrated Correction. 5: Press the "Mode/▲" key to switch to the milligram/liter "mg/L" unit, and you can start the measurement. 6: Power-on display "SLO" is "normal start" (factory setting), you must wait 5~10 minutes for the reading to be stable. Power-on display "FAS" is "quick start", the reading is stable after a few seconds, and you can start measuring , But the electrolyte consumption is relatively fast; when it needs to be turned on to measure, and the water temperature is low and the response speed is slow, it can be set to "quick start". In the measurement mode, press and hold the "Recall" + "Enter" keys at the same time for more than 3 seconds to switch to "Conventional" "Start" and "Quick Start" can also be switched during setting. 7: If there is no key operation for 1 hour, it will automatically shut down; if you want to cancel the automatic shutdown, press and hold the "SET+Mode/▲"" key at the same time in the shutdown state, and the instrument will automatically shut down until the word "n" is displayed. It will continue to power on until the battery is depleted. Package List: 1 x Dissolved Oxygen Meter(Battery Not Included)1 x Dissolved Oxygen Probe1 x Syringe (with Needle)1 x Probe Protective Cover (with Rubber Ring) 1 x Gauze1 x Sandpaper1 x Screwdriver1 x Manual 1 x Tool Box