The Stereo-Pak was adapted from the Fidelipac cartridge design by Earl "Madman" Muntz in 1962, in partnership with Eash, as a way to play pre-recorded tapes in cars.

[5] The endless loop tape cartridge was designed in 1952 by Bernard Cousino of Toledo, Ohio.

Muntz developed and marketed a variety of mobile and stationary players and recorders for his 4-track tapes.

[9] The B- and C-size carts would have their stereo sound split to mono and be used for background music systems all the way up to the early 1990s, when digital took over.

[citation needed] After riding in Muntz's car and listening to his 4-track cartridge system, electronics and aerospace entrepreneur Bill Lear had an employee of Lear Jet Corporation create a modified derivative, resulting in the more convenient and long-playing 8-track cartridge system, which quickly supplanted and surpassed the 4-track in the market until being surpassed, itself, by the cassette tape system.