iTunes is a Media Player on iOS, Windows, and Mac, and a media store from Apple Inc. that sells many music tracks and singles, including ones from the Sonic the Hedgehog series. They have been selling music tracks related to Sonic ever since the Sonic Rush soundtrack album Sonic Rush Original Groove Rush, and the Sonic Riders series' soundtracks were released. After that, they have sold the soundtracks to Sonic the Hedgehog 4: Episode I, Sonic the Hedgehog 4: Episode II, Sonic Colors, and Sonic Unleashed. For Sonic's 20th anniversary, they released the Sonic Generations soundtrack along with releasing a soundtrack from past Sonic games, with the name "20th Anniversary edition" attached to the end, from the oldest game, being the Sonic Adventure soundtrack, and the newest, being the Sonic and the Black Knight soundtrack. In addition to music, it also sells books, apps and games, movies, TV shows, and others, much of which can also be used on iOS devices.
iTunes and the iTunes store has competition with other media distributors since the early 2000s, including Amazon MP3 (which it also sells from most of the soundtracks from Sonic Games), Google Play Music, and others, although due to the fact some services are unavailable in Japan, Sega cannot sell the soundtracks to other distributors until it is available in Japan.