HM Digital SM-1 In-Line Single TDS Monitor, 0-9990 ppm Range, +/- 2% Readout Accuracy

How Pure is Your Water? HM Digital's SM-1 is a single inline monitor that measures TDS from 0 to 9990 ppm. It includes batteries, a single sensor and one 1/4" quick-connect T-fitting. The SM-1 is an easy and convenient method of determining TDS levels for water filtration/purification systems such as reverse osmosis (RO), deionization (DI), distillation and more. It's very useful for coolers or under-the-sink systems.