Hanna HI 9146-04 is a water-resistant, microprocessor-based, Dissolved Oxygen meter with automatic temperature compensation (ATC). D.O. measurements can be displayed in parts per million (ppm=mg/L) or in % of saturation. The temperature range is indicated in Celsius from 0 to 50°C with 0.1 resolution. This meter also allows manual compensation of altitude and salinity values. The polarographic probe with a four meter cable is supplied with the instrument and includes a protective cover for the membrane. A HOLD button allows the user to freeze readings on the LCD. HI 9146 can be powered with batteries (with low battery indicator) or through a 12 Vdc adapter.