This is the very popular 2.4GHz XBee XBP24-AUI-001 module from Digi.
The Pro series have the same pinout and command set of the basic series with an increase output power of 60mW! These modules take the 802.15.4 stack (the basis for Zigbee) and wrap it into a simple to use serial command set.
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.

If you are looking for distance, this module combined with a large 2.4GHz antenna is just about the longest range there is.
Better performance than the chip antenna because of the ability to add a higher-sensitivity antenna.

Note: Please check with your local laws regarding radio communication.

 

Features:

• 3.3V @ 215mA
• 250kbps Max data rate
• 60mW output (+18dBm)
• 1 mile (1500m) range
• Fully FCC certified
• 6 10-bit ADC input pins
• 8 digital IO pins
• 128-bit encryption
• Local or over-air configuration
• AT or API command set
• External Antenna Required

Documents:

• Digi XBee Page
• Datasheet
• Product Manual
• Dimensional Drawings
• Digi Examples and Guides
• X-CTU Software