The DO210 is a Dissolved Oxygen Meter which measures DO from 0 to 20.0mg/L, Oxygen Percent from 0 to 100.0% and Temperature with ATC. This meter features Adjustable Altitude and Salinity Compensation as well as min, max and data hold functions. Complete with DO probe with membrane and 39" (1m) cable, two spare replacement membranes, electrolyte, 9V battery and soft case.