The 4074A is a low power VHF transmitting double triode that would have been used in push pull with a common tuned anode coil connected across the twin top caps. The HT would be fed into the tank circuit centre tap. The base is ceramic for better resistance to heat and humidity at altitude etc.
The twin anodes.
Looking at the face of one anode.
A closer view.
The top mica: round cathode tubes and shaped heat-sinks on the control grids for maximum cooling area.
The classic envelope is 45 mm in diameter and, excluding the UX7 base pins, is 112 mm tall.
