The VS110 is a cold cathode voltage stabiliser. VS111 is the RAF designation and AW3 is the UK Army designation. Both types were renamed CV1110.
The striking voltage is 180 volts, and the stabilised working voltage is 120 Volts. For currents of between 6 - 75 mA the voltage is maintained to five volts of the target value of 120 Volts but can vary up to 10 Volts. The VS110A has a maximum voltage variation of five Volts.
Such valves would be used to achieve stable voltages for sensitive circuits such as oscillators. Also such a tube run at constant current would form a reference voltage for a valve voltage regulator. Oscilloscopes and radar displays would be fed from fully stabilised supplies.
This exhibit is unusual in that a valve for the UK government carries a makers label.
The Marconi paper label.
The top of the anode cylinder is closed.
Inside the cylinder is a support that is shaped like an inverted J with a flat top. From the descending arm of that support is a thin wire that connects to a shorter flat topped inverted J support. Most stabilisers just have a single vertical rod for the centre electrode - cathode. This has a priming anode.
The balloon envelope is 49 mm in diameter and, excluding the B4 base pins, is 104 mm tall.