Looking remarkably like
the battery it was intended to replace, this battery eliminator
must have been a tricky design proposition for the Vidor engineers.
As you can see from the label
it supplies only 90 volts HT and 1.4 volts LT so is of comparatively
recent manufacture compared with the others in my collection.
1.4 volt valves were used in
most post WW2 portables. Early sets still used octal-based valves
but the majority of sets, until the arrival of transistor sets,
used all-glass B7G varieties.
Batteries were expensive so
the use of a portable radio in the home could economically use
a power unit such as the one from Vidor. However, as this was
quite expensive, I guess it was a rare item.