Features1With automatic temperature compensation function, the temperature of the solution can be automatically compensated for 0?40, and the reading is accurate and stable. 2It is suitable for freshwater aquaculture, marine aquaculture, swimming pools, beverage factories, sewage treatment plants, and laboratories. 3Small pen?shaped design, light and easy to move, you can test water anywhere to get the purest water. 4High accuracy, quick response, quick test results can be detected, any 0.0?40.0mg/L liquid can be tested. 5The digital screen display with backlight makes the data read more clear and convenient.SpecificationItem Type: Dissolved Oxygen MeterMaterial: ABSWeight: Approx. 328g/11.6ozDissolved Oxygen Meter Size: Approx. 35 x 155mm/1.4 x 6.1inElectrode Length: Approx. 150mm/5.9inCable Length: Approx. 1.1m/3.6ftMeasuring Range:Dissolution: 0.0-40.0mg/LDissolved Oxygen Saturation: 0.0-300.0%Temperature: 0.1-40.0; 32.0-104.0Resolution:Dissolution: 0.1mg/LDissolved Oxygen Saturation: 0.1%Temperature: 0.1; 0.1Accuracy:Dissolution: 1.5%F.SDissolved Oxygen Saturation: 1.5%F.STemperature: 0.5Calibration 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: 0-40Battery Level: Low Battery WarningBacklight: Support Automatic BacklightPower Supply: Automatic Shutdown for About 8 MinutesBattery 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 temperature2. 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 List1 x Dissolved Oxygen Meter(Battery Not Included) 1 x Electrode 6 x Replaceable Electrode Tip 1 x Instruction