Ars Technica described these about two years ago in "Forgotten audio formats: The flexi disc." https://arstechnica.com/gadgets/2017/04/forgotten-audio-formats-

Ars Technica described these about two years ago in "Forgotten audio formats: The flexi disc." https://arstechnica.com/gadgets/2017/04/forgotten-audio-formats-flexi-disc/ https://arstechnica.com/gadgets/2017/04/forgotten-audio-form...