For a list of all currently documented Atmel chipsets with specifications, see Atmel.
"AR503AB-2" and "Rev: T1.0" is silkscreened on the board in the FCC photos.
There is a sticker with a MAC address affixed to the board in the FCC photos. The MAC address is 0090D1006C4B (Leichu OUI, used mainly by Eumitcom manuf. gear). It is presumed this device was designed when Eumitcom was still independent.