By doubling the number of tracks from 4 to 8, the recording length doubled to 80 minutes. In 1964, Lear's aircraft company constructed 100 demonstration Stereo 8 players for distribution to executives at RCA and the auto companies. The popularity of both four-track and eight-track cartridges grew from the booming automobile industry. In September 1965, the Ford Motor Company introduced factory-installed and dealer-installed eight-track tape players as an option on three of its 1966 models (the sporty Mustang, luxurious Thunderbird, and high-end Lincoln), and RCA Victor introduced 175 Stereo-8 Cartridges from its RCA Victor and RCA Camden labels of recording artists catalogs. By the 1967 model year, all of Ford's vehicles offered this tape player upgrade option. Most of the initial factory installations were separate players from the radio (such as shown in the image), but dashboard mounted 8-track units were offered in combination with an AM radio, as well as with AM/FM receivers. Muntz, and a few other manufacturers, also offered 4/8 or "12-track" players that were capable of playing cartridges of either format, 4-track or 8-track. With the backing of the U.S. automakers, the eight-track format quickly won out over the four-track format, with Muntz abandoning it completely by late 1970. The 8-track format gained steadily in popularity because of its convenience and portability. Home players were introduced in 1966 that allowed consumers to share tapes between their homes and portable systems. By the late 1960s, the 8-track segment was the largest in the consumer electronics market and the popularity of 8-track systems for cars helped generate demand for home units. "Boombox" type portable players were also popular but eight-track player/recorders failed to gain wide popularity and few manufacturers offered them except for manufacturer Tandy Corporation (for its Radio Shack electronics stores). With the availability of cartridge systems for the home, consumers started thinking of eight-tracks as a viable alternative to 33 rpm album style vinyl records, not only as a convenience for the car. Also by the late 1960s, prerecorded releases on the 8-track tape format began to arrive within a month of the vinyl release. The 8-track format became by far the most popular and offered the largest music library of all the tape systems. Eight-track players were fitted as standard equipment in most Rolls-Royce and Bentley cars of the period for sale in Great Britain and worldwide. Optional 8-track players were available in many cars and trucks through the early 1980s.