Whoa. Have you guys EVER seen/heard/owned a Tefifon? Nope?! I didn't think so! The Tefifon was a German-engineered and -manufactured tape deck that used 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" the tape surface. So, tho' it was a tape, instead of sound stored magnetically, it had grooves like what we see on records.
The grooves were embossed in a helical fashion across the width of the tape, much similar to Dictaphone's Dictabelt format, and were read with a stylus and amplified pickup in the player's transport. A Tefifon cartridge could hold up to four hours of music, therefore, most released for the format were usually compilations of popular hits or dance music, operas and operettas.
Gosh, it's a cool-looking machine, sounds good, could run for hours, and the tapes are even smart looking. So, why'd it fail? The machine was on the market from the late '40s through the mid '60s, but was shuttered after struggling, and failing, to compete with the Long Play album and tape formats. Also, there was a problem of major label disinterest—since most Tefifon releases were by little-known artists, there was little demand. Sidebar for audio trainspotters: The Tefifton was almost exclusively sold in Germany, but was marketed in the States in the mid '60s "under the 'Westrex' name."