The DO210 is a Dissolved Oxygen Meter that measures DO from 0 to 20.0mg/L, oxygen percentage from 0 to 100.0%, and temperature using ATC. This meter includes adjustable altitude and salinity compensation, as well as min, max, and data hold options. Includes a DO probe with membrane and 39" (1m) cable, two spare replacement membranes, electrolyte, 9V battery, and protective case.