The RCA 7554 is a UHF pencil power triode for use at up to 5 GHz and at heights of up to 100,000 feet. The main application would be military.
The anode on the left, ceramic insulator, control grid, ceramic insulator, cathode and finally the heater wires. The 7554 would be mounted in a co-axial cavity and probably operated with a grounded grid.
The RCA name and Made in USA.
The copper anode with seal and silver plating.
The heater connections and two stubs for internal mountings.
The pencil envelope is six mm in diameter and, excluding the base pins, is 35 mm tall.
Reference: Data-sheet. Type 7554 was first introduced in 1959.