US-Navy CFT-15E Early 1940's UHF power triode.
CFT-15E Triode
A WWII aircraft radar triode operating in the B- and C-band range at 400 - 600 MHz. (~50cm.) The heater draws 4.2A at 5.5V. The maximum anode dissipation is 20W continuous but when used in pulse mode up to 15 kW can be produced.
The grid is a cage of vertical bars, as seen in a few other RF power valves, e.g. 3/500Z and fed from the top. The heater is formed from a spiral supported by a central bar, so that both connections are made from the same end. The anode is side fed. This arrangement allows for the use of RF screening between the anode, grid and cathode circuits and of very high anode voltages, up to 15 kV.