The following note taken directly from their manual

The EZ−Guide 500 lightbar can import variable rate prescription files in Shapefile format. The application rate information from the prescription attribute file (.dbf) is sent to EZ−Boom or a supported third party variable rate controllers to control flow rates.

Note: All prescription files must use geographic WGS84 for the coordinate system.

Note: All prescriptions must be imported (copied) from the USB drive to the EZ−Guide 500 lightbar. The lightbar cannot read prescriptions directly from a USB drive

Note: The EZ−Guide 500 will only detect prescription files located in the \AgGPS\Prescriptions\ folder on the USB drive.

Note: If the USB drive does not already have the correct folders set up, you can insert the USB drive into the EZ−Guide 500 lightbar, turn it on and wait until the lightbar has detected the USB drive, and then turn the lightbar off. The lightbar will automatically create the folders on the USB drive.