Dissolved Oxygen Meter Kit Reliable DO readings at a reasonable price. Measures dissolved oxygen to determine water quality in environmental testing, labs, industrial and municipal waste water, aquariums and fish hatcheries. The back-lit display simultaneously displays dissolved oxygen (in % or mg/L) and temperature readings (in 'C or 'F). Automatic temperature compensation as well as manual compensation for salinity and altitude (all factors affecting DO readings). Features simple one-button calibration to air. DO probe heads include built in membranes and screw on and off for easy replacement. Also functions as a pH, ORP, Conductivity, TDS or Salinity meter when used with the optional probes. Comes in a hard carrying case complete with DO probe, 2 spare probe heads, electrolyte, instructions and a 9V battery. EPA Equivalency Method: 360.1 and Alpha Method 2580.1992.