The go-to for hand held conductivity pens. The Bluelab® Conductivity Pen measures conductivity and temperature and simply tells you the amount of nutrients in your solution. 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 robust, convenient, and 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. Includes one AAA replaceable battery.