The wireless sd shield allows an arduino board to communicate wirelessly using a wireless module it is based on the xbee modules from digi but can use any module with the same footprint the module can communicate up to 100 feet indoors or 300 feet outdoors with line of sight it can be used as a serialusb replacement or you can put it into a command mode and configure it for a variety of broadcast and mesh networking options the shields breaks out each of the xbees pins to a through hole