COM-100 Professional EC/TDS/Temperature Meter is a waterproof (IP-67) digital water testing device designed for RO water purifiers, aquariums, hydroponics, laboratories, pools, and drinking water. It measures EC, TDS, salinity, and temperature with Automatic Temperature Compensation (ATC) for highly accurate readings. Features include push-button digital calibration, data-hold, auto-off, large LCD display, and replaceable SP-C1 sensor. Comes factory-calibrated with 1413 µS solution, translucent cap, AAA batteries, and lanyard for easy use anywhere.