In 1924, Kodak invented 16-mm film, which became popular for home use, and then later developed 8-mm film. After that point, the public could purchase a film projector for one of those film formats and rent or buy home-use prints of some cartoons, short comedies, and brief "highlights" reels edited from feature films. In the case of the 16-mm format, most of these were available with an optical soundtrack. Some entire feature films in 16-mm could be rented or bought. The 8-mm films almost never ran longer than 10 minutes; only a few were available with a magnetic soundtrack late in the life[colloquialism?] of the format. The Super 8 film format, introduced in 1965, was marketed for making home movies, but it also boosted the popularity of show-at-home films. Eventually, longer, edited-down versions of feature films were issued, which increasingly came in color and with a magnetic soundtrack, but in comparison to modern[specify] technologies, film projection was still quite expensive and difficult to use. As a result, home viewing of films remained an activity only for people willing and able to invest large amounts of money in projectors, screens, and film prints, and it therefore made little revenue for film companies.