The Milwaukee EC60 PRO Conductivity Tester is designed for hydroponic and other growers to help you make sure that your plants have the ideal amount of nutrient avaiable. Keep EC in your target range to help your achieve better results. Measures conductivity and TDS with automatic temperature compensation. Ideal range for hydroponic and other growers (0.00 to 20.00mS/cm).Units in mS/cm or ppt easily convertable to ppm. Factory calibrated with the ability to recalibrate if needed. Replaceable electrode. Fully waterproof to IP65. Approximately 100 hours of use (4 x 1.5V batteries included).