Never seen this before... have you ?

[Externet]

A sixteen inch vinyl record. Next to a standard twelve inch 'long play' for comparison :

What do you know about ?

 

[Bluejets]

No but as usual, Google does. Transcription disc.

https://en.wikipedia.org/wiki/Phonograph_record

 

[Martaine2005]

Yeah, transcription disc typical for radio broadcasts in the 30s, 40s.
I think some played from the inside out and were 33 and 78rpm.
I had one years ago that wouldn’t fit my turntable, so I threw it like a frisbee . It was amazing and I never found it. Just simply vanished.

Martin