All we know of this exhibit is that it is an experimental coaxial transmitting triode.
The heater/filament leads are substantial copper braid indicating high current. The grid ring connects to a conical wire cage that can be seen in the picture. The anode is a copper bell connected to a significant cooling fin assembly.
This has to be an essay in the art of building of high power, high frequency transmitting valves.
The wide glass tube envelope is 55 mm in diameter and, the length is 178 mm.
Reference: Observation. Type Experimental was first introduced in 1917.
Updated January 22, 2013.