This is the XBee XB24-Z7WIT-004 module from Digi. Series 2 improves on the power output and data protocol. Series 2 modules allow you to create complex mesh networks based on the XBee ZB ZigBee mesh firmware. These modules allow a very reliable and simple communication between microcontrollers, computers, systems, really anything with a serial port! Point to point and multi-point networks are supported.
These are essentially the same hardware as the older Series 2.5, but have updated firmware. They will work with Series 2.5 modules if you update the firmware through X-CTU.
Note: If you are looking for a simple point-to-point configuration, you might want to try the Series 1 instead. The Series 2 requires considerable setup and configuration. We highly recommend Building Wireless Sensor Networks as a guide for setting up mesh networks.
Note: Series 1 and Series 2 XBee modules have the same pin-out. However, Series 1 modules cannot communicate with Series 2 modules.
Note: If you are using these outside of the United States, please check with your local laws regarding radio communication.