Handheld Dissolved Oxygen Meters, Dissolved Oxygen Range 0 to 20 ppm, Oxygen Concentration 1 to 200 Percent, Waterproof IP67, Displayed Temperature Range -6 Degrees to 46 Degrees C, 21.2 Degrees to 114.8 Degrees F, Salinity Range 0 to 40 ppt, Operating Temp. Range (F) 0 Degrees to 50 Degrees C, Operating Temp. Range (C) 32 Degrees to 122 Degrees F, Display Graphic, Auto Power Off Auto Power Off, Memory 50 Data Sets, Calibration Back Up, Cable Length 1 m, Power Source 9V Battery