The CV118 is a WWII military HF receiving pentode valve. Externally it is covered by an external screening metallisation. It functioned as a mixer with the P61 (VR66) as a low noise oscillator.
With the grid at the top cap, this is the normal pattern for RF and IF amplifier valves of the period. Providing high gain in tuned anode circuit applications.
This valve type was used in air-borne radar particularly GEE.
The KB/EN identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the EN identifies the maker as Thorn-AEI, Sunderland.
The MOD up arrow.
The rest of the envelope is plain zinc loaded screening paint.
The classic envelope is 32 mm in diameter and, excluding the MO base pins, is 79 mm tall.
References: Data-sheet & 1040. Type CV118 was first introduced in 1941. See also1941 adverts.