Bernard Cousino in Toledo developed an endless loop tape recorder in 1952 as a point-of-sale device inside a cow's head for a dairy company; he patented a double-coated tape that 3M began to manufacture; he formed the Cousino Electronics Co. to sell the "Audio Vendor" cartridge holding a small "pack" of tape (without a reel). George Eash in Toledo designed a similar cartridge and sold it to Telepro who called it the Fidelipac cartridge in 1959 that was used in the 1960s by radio stations. Earl Muntz in California was a former Kaiser auto dealer who sold TVs that he manufactured by the Muntz Television Inc.; he sold his TV company in 1962 to market the Fidelipac under the name Muntz Stereo-Pak for autos, priced as low as $49.95, that used transistorized electronics and 2 stereo heads for 4-track 1/4-inch tape. His player and its 4-track tapes were successful in California in the new "autosound" market and spread eastward. CBS and Peter Goldmark with 3M developed in 1962 a tape cartridge machine that used .15 inch tape at 1-7/8 ips in 3-channel stereo, was self-threading; but too expensive at $450 and was withdrawn 1965.
In 1963 Lear had become a distributor for Muntz and put the 4-track Fidelipac in his jet. He worked on the 8-track device in 1964, ordering small heads from Nortronics of Michigan. His cartridge was the same size as the Fidelipac and used the same double-coated tape. The crucial difference was the new heads from Nortronic. He made 100 Learjet Stereo-Eight players in 1964 for executives of RCA and the auto companies. Ford agreed to install the player in its 1966 models as an option (helped by Lear's ties with Motorola who was the electronics supplier for Ford). RCA agreed to release 175 recordings in 8-track. By 1967, 2.4 million players were sold, and the 8-track player became the first tape format to succeed in the mass market. However, the compact cassette would eventually win the marketplace.