The ultimate handy solution for measuring conductivity (EC/PPM) and temperature! The Bluelab EC Pen simply tells you that your plants have the right amount of nutrient in your solution and lets you know if adjustments are needed. This pen can monitor EC/PPM of solution. The Bluelab Conductivity Pen also measures the temperature of the solution. Temperature affects the growth rate so a solution temperature of 65-72øF is recommended for most crops. Includes a 1 year warranty.