The Homogen resistors were incredibly expensive components at the time
but they were also the best, you could buy.
I never found one in a Bang & Olufsen radio, though.
They came in a wide range of ohmic values (not following todays standards) and were all of the
same physical size (apprx. 30 x 8 x 4mm). They came with their ohmic values either cast into the
housing or stamped on one side.
A B&O logo was always cast on the other side.
I was told that the initial production series were not of (close) predicted values,
instead the components were measured and stamped accordingly after being produced.
Later, if the story is true, the production control was bettered and the
ohmic values were then cast into the housing itself during production.
I have the above mentioned different versions in my collection and
I also have the 4MOhm shown here, where the "MOhm" is cast in the bakelite
housing (protruding) and the "4" is engraved into the material, making it a
third variant.
Today, their ohmic values have all gone high, 50-100% or more.
Martin