The Dixon FT151P-12 is a Checkmate Plug-n-Play Overfill Sensor for Flotech overfill systems. The cast aluminum housing contains a Plug-n-Play prope that signal the loading rack to close the fuel supply valve when wetted, preventing the spill of product. It is easy to install and fits a 2-inch NPT threaded port or a 2-3/8 inch diameter tank opening.