Milwaukee MC410 TDS - PPM Monitor Old SMS410 Smart Monitoring System Range: 0 –1990 ppm with Accuracy of ±2% Full Scale and 1 Point Manual Calibration. Set Point Range 700 to 1800 ppm, and LED Visual Alarm Active when reading is Higher or Lower ( user select ) than the set point. Supplied with 12 V DC Power, MA812/2 PPM Probe & 20 ml. 1382 ppm Sachet Calibration Solution and Screwdriver for Calibration. - Unit comes with Mounting Kit and Probe Holder