The Radio/Wireless Transceiver integrates a complete 2.4GHz RF transceiver, RF synthesizer,
and baseband logic including the Enhanced ShockBurst™ hardware protocol accelerator supporting
a high-speed SPI interface for the application controller.
*Note: This is not an original Arduino brand product.
I havent received mine yet but judging from the photo, it's using a NRF24L01p chipset. You can find the datasheet here http://www.sunrom.com/media/files/p/402/nRF24L01P_Datasheet.pdf and more info at http://www.sunrom.com/402. Ill post when I get some rough measurements for range LOS