Feature: 1. With automatic temperature compensation function, the temperature of the solution can be automatically compensated for 0‑40℃, and the reading is accurate and stable. 2. It is suitable for freshwater aquaculture, marine aquaculture, swimming pools, beverage factories, sewage treatment plants, and laboratories. 3. Small pen‑shaped design, light and easy to move, you can test water anywhere to get the purest water. 4. High accuracy, quick response, quick test results can be detected, any 0.0‑40.0mg/L liquid can be tested. 5. The digital screen display with backlight makes the data read more clear and convenient. Specification: Item Type: Dissolved Oxygen Meter Material: ABS Weight: Approx. 328g/11.6oz Dissolved Oxygen Meter Size: Approx. 35 x 155mm/1.4 x 6.1in Electrode Length: Approx. 150mm/5.9in Cable Length: Approx. 1.1m/3.6ftMeasuring Range: Dissolution: 0.0-40.0mg/L Dissolved Oxygen Saturation: 0.0-300.0% Temperature: 0.1-40.0℃; 32.0-104.0℉Resolution: Dissolution: 0.1mg/L Dissolved Oxygen Saturation: 0.1% Temperature: 0.1℃; 0.1℉Accuracy: Dissolution: ±1.5%F.S Dissolved Oxygen Saturation: ±1.5%F.S Temperature: ±0.5℃Calibration Method: Support single-point or double-point automatic calibration, that is, 0 point or automatic 100% calibration in the air.Response Time: ≤45s (90% Response at 20℃) Automatic Temperature Compensation Range: 0-40℃ Battery Level: Low Battery Warning Backlight: Support Automatic Backlight Power Supply: Automatic Shutdown for About 8 Minutes Battery Attributes: 3 x 1.5V 150MAH LR44 Battery (Battery Not Included) Use Environment: 0.1-40.0℃ RH Maximum 90% Instructions for Use: 1. Connect the electrodes, press the power button, power on, the screen will display mg/L temperature 2. Short press the HOLD button to lock the value, long press the TEMP button to switch ℃ or ℉ 3. Short press the MODE button to switch mg/L or% 4. Long press the CAL button to calibrate in the air. The screen displays 100.0%. After the flashing is completed, the calibration is successful. If calibrated in anaerobic water, 0.0% is displayed.. Package List: 1 x Dissolved Oxygen Meter(Battery Not Included)1 x Electrode6 x Replaceable Electrode Tip1 x Instruction Note: 1. Please allow 0‑2 cm error due to manual measurement. Thanks for your understanding.2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.3. This product does not come with electrode filling fluid.