The E122FC is presumed to be a valve but we have no information at all.
The top of the plastic outer showing the identification has been written by hand. This suggests an experimental device.
The miniature five pin base with a paxolin ring. The base is identical to that used on E122ER.
The socket for the miniature five pin valves.
The underside of the valve base.
The envelope is 22 mm in diameter, and excluding the base pins is 23 mm tall.
Updated February 11, 2013.