This Tungsram voltage stabiliser is marked VR90/0B3 0B3 and is a gas filled discharge valve that maintains 90 Volts within 5 Volts for currents of between 5 and 30 mA.
Internally pins 3 and 7 are linked. This shorting link is designed to protect the connected equipment from overload, as when the stabiliser is removed the supplied circuit is disconnected.
The cathode tube is ribbed to give mechanical stability to the thin sheet metal.
Through the centre of the top mica is the anode rod.
The classic envelope is 38 mm in diameter, and excluding the IO base pins is 89 mm tall.
