Sanyo Tape Cartridge

The Sanyo Tape Cartridge, also marketed as the Sears Tape Cartridge, was a 1960s competitor to the Philips Audio Cassette, very similar to it but a slightly different size so it didn't fit in the same recorders/players.

The interesting Techmoan video series on YouTube did a video on this format (linked below) that discussed the efforts to digitize audio from one of these cartridges/cassettes, which ultimately succeeded (despite lack of access to a Sanyo/Sears machine to play it) through the contrivance of unscrewing the cartridge, transferring the tape mini-reels inside to a regular cassette (the size of the tape itself is close enough so it fits) and then playing it -- the result is that the audio plays backwards, because the tracks for the two sides are in reverse positions from normal cassettes, but digital audio editors make it easy to "flip" it to play correctly.

Links

 * Video on this format