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 ...