Buffalo WLAE-AG300N

Overview
"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 / 2593A20 s.

Links of Interest

 * Manual (also via archive.org)