Milwaukee TDS meter MW401 PRO is a portable TDS (Total Dissolved Solids) meter with automatic temperature compensation for daily use. The measurement of the TDS value provides information about the effectiveness of the filter and is equally useful in the production of osmosis water. The Milwaukee TDS meter MW401 PRO comes complete with electrode and calibration solution.Milwaukee TDS Meter MW401 PRO+ fast, easy-to-read results with large digital LCD display+ measuring range: 0 - 1999 mg/L (ppm)+ resolution: 1 mg/L+ accuracy: +/- 2%+ temperature compensation: automatic, from 5 to 50C+ supplied with conductivity probe attached to a 3 foot cable+ lightweight and portable+ dimensions: 143 x 80 x 32 mm+ auto shut off and low power demand for approx. 300 hours of continuous use+ battery, calibration fluid and screw driver included