TDS monitor, range: 0-1990 ppm with accuracy of 2% full scale and with 1 point manual calibration and automatic temperature compensation. Set point range 700 to 1800 ppm, and led visual alarm active when reading is lower than set point. Supplied with 12v DC power adapter, MA812B/2 conductivity probe and 20ml. 1500 ppm packet buffer solution and screwdriver for calibration.