The Crazyradio 2.4GHz nRF24LU1 USB Radio is the official radio dongle for the Crazyflie Nano Quadcopter. It is a 2.4GHz USB radio dongle based on the nRF24LU1+ chip. The design includes a 2x5 header (not mounted) where the dongle can be connected and powered from a source other than USB. It also has two indicator LEDs. The dongle can communicate with any project using a compatible Semiconductor radio chip. A bootloader on the dongle enables firmware updates without using any external programmer. It can also be programmed over SPI, which is available via the header.
Robotshop Web Site: http://www.robotshop.com/en/crazyradio-24ghz-nrf24lu1-usb-radio.html