This Vidor advert from June 1950 extols the virtues of their multi-voltage radio battery.  With outputs for high tension (120V) and low tension (and / or grid bias) of 3V, 4½V and 6V this complex battery was well suited to portable radios of the time.

Whilst they say that Vidor "last a month longer", pasted over an annual calendar - they don't exactly say how long that is!

What a beast - and of course impossible to source these days.  Collectors of portables from this era are condemned to taping together multiple modern batteries or building quite complex mains based battery eliminators.

Vidor Ltd.
Erith
Kent