The Muntz Stereo-Pak, commonly known as the 4-track cartridge, is a magnetic tape sound recording cartridge technology.

The Fidelipac, commonly known as a "NAB cartridge" or simply "cart", is a magnetic tape sound recording format used for radio broadcasting for playback of material over the air including radio commercials, jingles, station identifications, and music as well as for indoor background music. Fidelipac is the official name of the industry standard audio tape cartridge.