This exhibit carries no identification but is obviously a planar UHF triode. On test the cathode glowed at about the right colour when passing 3.65 amps at 6.3 Volts. This is some ten times the heater power of the TD03-10 disc seal triode. This suggests an output power of around 30 Watts.
From left to right: heater, heater and cathode, grid ring and anode.
The anode has internal fins that open into the well near the glass/metal seal. Probably this would be cooled by forced air directed into the top of the anode and exhausted against the glass/metal seal.
Close-up of the grid. A central strip passes across the grid and there is a corresponding notch in the anode. The grid is essentially a frame grid with the wire under considerable tension to ensure a flat surface. The carrier is fixed to the copper support by screws that are tapped into the copper.
The wide glass tube envelope is 46 mm in diameter, and including the base is 123 mm tall.