Extech Instruments DO210 Compact Dissolved Oxygen Meter, Green/Black

Amazon

Automatic temperature compensation via temperature probe sensor built into polarography type oxygen probe Adjustable altitude and salinity compensation Min/max and data hold functions Auto power off with disable feature, Weight: 0.992080179 Pounds, Manufacturer: Extech

Test-meter.co.uk

Precision DO meter. 0-20mg/l oxygen, 0-50°C temp range. Detachable 1m probe. Auto temp/salinity compensation. Digital display. Industrial/water analysis applications. Includes spare membranes, battery, case.