1[Accuracy Instrument] DO9100 is an accuracy instrument for measuring dissolved oxygen and temperature. With built in microcomputer processor to calculate and compensate all measurement data related to dissolved oxygen and temperature. 2[Probe] A membrane with a polarographic sensor and a thermistor for temperature measurement and temperature compensation. The permeable membrane separates the measured solution from the sensing electrode and allows oxygen to pass through the membrane to react. 3[Digital Display Screen] It is equipped with a clear digital display screen, which is convenient for reading data. If not in use, it will automatically shut down in 8 minutes, with low battery prompt, detachable probe, and easy to replace. 4[Temperature Compensation Function] The solubility of oxygen will be affected by temperature, atmospheric pressure and salinity. Our instrument has a temperature compensation function, which can meet normal use. 5[Wide Application] Suitable for measuring the dissolved oxygen level and temperature in aquariums, swimming pools, pond, freshwater aquaculture, marine aquaculture, school teaching experiments, laboratory sterile environment, aquaculture, scientific research and other fields. Item Type: Dissolved Oxygen Meter Material: ABS Model: DO9100 Battery: 1.5V LR44 x 3 Battery (Battery Not Included) Uses: Suitable for freshwater aquaculture, marine aquaculture, swimming pools, beverage factories, sewage treatment plants, laboratories. Measuring Range Oxygen concentration (mg/L) 0.0-40.0mg/L Dissolved Oxygen Saturation (%) 0.0-300.0% Temperature 0.0-40.0 32.0-104.0 Resolution Oxygen concentration (mg/L) 0.1mg/L Dissolved Oxygen Saturation (%) 0.10% Temperature 0.1C; 0.1F Accuracy Oxygen concentration (mg/L) 1.5%F.S Dissolved Oxygen Saturation (%) 1.5%F.S Temperature 0.5 Calibration Mode Support single point or double point automatic calibration, that is, zero point or automatic 100% calibration in air Response Time 45s (response at 20) Temperature Compensation Range Automatic (0-40) Height Compensation Without Battery Power Low battery warning Shut Down Automatic shutdown about 15 minutes Use Environment 0.1-40.0 RH maximum 90%1 x Host (Battery Not Included) 1 x Dissolved Oxygen Electrode 6 x Dissolved Oxygen Membrane Group 1 x Manual