Plants get their nutrition from minerals but they can only get all the right minerals they need if certain conditions are right. A key factor that affects food uptake is whether the solution is acid or alkaline. This is measured in pH. The Bluelab pH Pen is the latest innovation for hand-held meters. It provides a compact, quick and handy way to manage the success of crops, to ensure maximum uptake of nutrients. Teamed with the Bluelab EC Pen or Bluelab ppm Pen, it is a handy, convenient and accurate system for ensuring optimum plant growth and health. Benefits Measures pH and temperature Selectable units for °C & °F Backlit LCD display Double junction probe (not replaceable) Successful pH calibration indicator Hold function Low battery warning Fully waterproof Auto off function Automatic temperature compensation