The Milwaukee Oxygen Meter MW600 PRO oxygen meter is a professional, reliable and robust measuring device for determining the oxygen content in aquariums, garden ponds, pools, etc. The device is suitable for daily, professional use as well as for the ambitious hobby aquarist.Milwaukee Oxygen Meter MW600 PRO+ fast, easy-to-read results with large digital LCD readout+ measuring range: 0.0 to 19.9 mg/L+ resolution: 0.1 mg/L+ accuracy: +/- 1.5%+ lightweight and portable+ simple 2 point open air calibration+ uses MA840 reinforced polarographic probe with an oxygen-permeable polytetrafluroethylene (PTFE) membrane sensor+ 5 o-rings, membranes and one protective cap included+ 10 feet probe cable for extra flexibility when testing+ 70 hours of battery life with continuous use (battery included) with low battery warning+ dimensions: 143 x 80 x 32 mm