Simply measure conductivity and temperature with the Bluelab pen. Keep track of nutrients in your solution for healthy plants. Conductivity is automatically compensated with the integrated temperature sensor. Provides a compact, quick, and accurate way to measure two key parameters for crop health. The accurate measurement system is fully waterproof, has a backlit LCD display, selectable units for conductivity and temperature, and is calibration optional. There is a hold reading function, low battery indicator, auto-off function, and automatic temperature compensation.