Buffalo WLAE-AG300N

AirStation N300 2-Port Dual Band Wireless Ethernet Bridge

Product page
 * Manual (also via archive.org)

"WRTA-266N_V00#A" and "19K-X06-8401R RoHS" is silkscreened on the board in the FCC photos.

On the OpenWrt Forums (w/ P/Ns)
 * The FEMs are specified as Skyworks (SiGe) SE2593A20 / 2593A20s.