FOUND! ARVIN 9219-cm-uhf television.

[dtvmcdonald]

I've got a good test of the USPS running. Two large and heavy boxes of 78 RPM
records won (at minimum bid prices) at the usual record auction. Shipped by
USPS media mail last Friday. Supposed to arrive by 9 PM tomorrow, Tuesday.
Currently "in transit".

This would be some sort of record for Media Mail.

This is almost on topic: they are played on a period-correct record player also
used as the audio of a pre-war TV, albeit with a replacement 7 gram pickup and
a counterweight.