Unfortunately the tube has no emission and the real purpose for this post is behind the tube which is a set of iron for another round plate tube that does the R-type X 4... the 304TL.
The bigger ones are the SE outputs that can take 200ma of plate current while putting out 40 watts at 50hz. They have bandwidth (-1dB) from 7hz to 49Khz and can do all of this due to the offset winding that runs the 12.5A filament current through the outputs in the opposite direction as the B+. This brings the other two chokes into play which are the 20mhy 12.5A filament chokes that keeps the offset winding from loading down the tube.
The set of 4 weighs in at 46 pounds of copper and amorphous and boy am I glad the topic of silver never came up.