The RSR2 measures sunlight,  a fundamental natural resource.  The first commercial application relates to designing and testing solar power plants that convert solar radiation into electricity.  There are myriad additional applications limited only by the need for light for most human activities.  Interestingly, our sensors come from Licor Environmental, whose primary business is measurments for agriculture.  Our data loggers come from Campbell Scientific, the world leader in highly accurate, rugged, low-power remote sensing devices.