| Milwaukee Portable TDS Meter [model SM401] SM401 PORTABLE TDS METER Model SM401 TDS meter - Range: 0.0 - 1990 ppm - with automatic temperature compensation and 1 point manual calibration supplied with MA811D/1 TDS probe, 9v battery, 20ml 1382 ppm packet buffer solution and screwdriver for calibration.  | Manufacturer's Product Information |  | | | | |