Unless you are German or collect vintage audio equipment, chances are you have never even heard of the Tefifon. That doesn’t mean it doesn’t have a Wikipedia page, since virtually everything has a Wikipedia page.
The Tefifon was a German-developed and manufactured audio playback format that utilized cartridges loaded with an endlessly looped reel of plastic tape (much like the later 4-track and 8-track magnetic audio tape cartridges) with grooves embossed on it, similar to the ones on a phonograph record.
Born in the 1950s, it never really caught on, but it’s a fascinating contraption. For a better sense of the Tefifon and how it works, I recommend this 11-minute video from a blog called Techmoan.
If you didn’t watch, the Tefifon did come with an accessory: “Remember, we’re talking 1957,” notes the narrator, “and we’ve got a remote control for our hi-fi.”
Commenters were impressed: “What an amazing piece of technology. I've never seen anything quite like it,” writes one. “4-hour cartridge! That's one hell of a long album.”
I found this fascinating in part because of the comparison between the Tefifon and an 8-track tape player, which was my music machine of choice during my teens and early 20s … until someone stole it from my car. It was a serious loss at the time.