Feature:1. With automatic temperature compensation that will automatically compensate for the solution temperature of 040 , it can provide you with an accurate and stable reading.2. Suitable for freshwater culture, mariculture, swimming pool, beverage factory, wastewater treatment plant and laboratory.3. Compact penshape design, lightweight for mobility, you can test water anywhere to get the purest water.4. High accuracy and quick response: fast to get the testing result and can test the oxygen value for any 0.0 20.0mg/L liquid which you wanna test.5. Adopts the digital screen display with backlight, which is more clear and convenient to read data.Specification:Condition: Brand NewItem Type: Dissolved Oxygen Meter Material: PlasticMeasuring Range:Dissolved Oxygen: 0.0- 20.0mg/LTemperature: 040CBasic Error:Dissolved Oxygen: 0.3mg/L Temperature: 1C Residual Current: 0.15mg/LResponse Time: 30s (90% response at 20C)Automatic Temperature Compensation Range: 040CPower: 4 x LR44 Button Battery (not included)Package List:1 x Dissolved Oxygen Meter 1 x Electrode3 x Replaceable Electrode Head1 x Instruction1 x Plastic BoxNote:Please note that the product is shipped without electrode filler.