The 2E22 is a directly heater pentode for RF power applications. It looks similar to the indirectly heated 807 but operates at higher voltages and produces more power. The ceramic insulators indicate the high anode voltages involved. The directly heated cathode avoids problems with heater/cathode shorts.
The suppressor grid has its own pin and can be used for modulation input. The 807 has g3 tied internally to the cathode.
Tung-Sol on the base cap. The brown may indicate a base for use in humid atmospheres.
The filament tension spring immediately indicate that this is directly heated.
The elliptical lower screen is normally only ever seen on an 807.
The classic envelope is 52 mm in diameter and, excluding the UX5 base pins, is 134 mm tall.
References: Data-sheet, 1040 & 1043. Type 2E22 was first introduced in 1945. See also1945 adverts.
