The Smart Portable TDS Meter is a sturdy, high-quality meter that is simple-to-use and comes complete with a TDS probe, 20mL calibration solution, 9V battery and screwdriver for calibration. This meter measures TDS with a range of 10-1990 ppm, resolution of 10 ppm, and an accuracy of ±2% full scale. Calibration is 1-point manual. The included 9V battery provides up to 300 hours of continuous use, so your customers get lots of use before needing to replace the battery. The Smart Portable TDS Meter carries a 2-year warranty; the probe carries a 1-year warranty.