It can mount directly onto your Arduino module. 3.3V power regulation and MOSFET level shifting on board. There are reset button and LEDs to indicate activity and power on DIN, DOUT, DIO5 and RSSI pins of the XBee. It's DIN and DOUT pins can be connected to UART pins or any digital pins on Arduino (default D2 and D3). With a 9x11 grid of 2.54mm/0.1" holes for prototyping.