The com-80 is an economically priced, reliable ec/tds meter that is ideal for testing applications such as hydroponics & gardening, pools & spas, aquariums & reef tanks, water ionizers, drinking water and more. Measures electrical conductivity (ec),total dissolved solids (tds).Excellent for nutrient testing. Four scales: ec: µs, ms; tds: ppm, ppt. This tester has automatic temperature compensation (atc) and is water resistant. Measurement range: 0-9990 µs; 0-5000 ppm; 0-9.9 ms; 0-5.0 ppt. Digital calibration (push button) to any point within the meter's range. Auto-off function, data-hold function and low-battery indicator with large and easy-to-read lcd screen includes simultaneous temperature reading. Factory calibrated: the com-80 meter is calibrated with a 1413 µs solution. The meter can be recalibrated with digital calibration using the push buttons. Includes a protective cap and batteries.