HM Digital EC-3 Handheld Electrical Conductivity (EC) Tester Meter with Case, 0 - 9990 &micro;S Measurement Range, 1&micro;S Resolution, +/- 2% Readout Accuracy The EC-3 is ideal for all water purification applications, waste water regulation, aquaculture, hydroponics, and colloidal silver The Handheld Conductivity Tester is idealfor consumer as well as commercial use The Conductivity Tester ishighly efficient and accuratedue to its advanced microprocessor technology Ideal for commercial use. Includes a carrying case with belt clip. Hold Function: Freeze the measurement to view it out of the water Auto-off function: the meter shuts off automatically after 10 minutes of non-use to conserve batteries. Built-in digital thermometer (Celsius only) ATC (Automatic Temperature Compensation)