An earlier magnetic tape cartridge technology introduced by Lear Jet in 1964 as Stereo 8, although widely known by its 8-track moniker. Stereo 8 was an 8-track version of the 4-track Muntz ...

The electronics from the cassette adapter are simply placed inside an old 8-track tape, with holes cut in the chassis for the charge port and on switch. Then, all you need to do is pop the adapter ...

the audio cassette became the standard for music playback in vehicles. See 8-track tape. The tape is recorded in two directions, which doubles its length (two monaural or four stereo tracks).