The CV1120 is an EHT half wave rectifier with a PIV rating of 14 kV. The CV valves were produced to a specification and made by more than one company.
The Cossor hand made SU2150A was the valve that best suited the design applications. This exhibit was made to the Cossor design.
The KB/K identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the K identifies the maker as ETEL, Electronic Tubes, High Wycombe.
The anode connects to the top cap but is supported on thin glass rods rising from the pinch. The ribs are to add mechanical strength to the thin nickel sheet that the anode is pressed from.
The rod cathode is oxide coated.
The balloon envelope is 50 mm in diameter, and excluding the B4 base pins is 112 mm tall.