Guitar Hero is a popular series of music vieo games published by RedOctane in partnership with Activision. The series is notable for its use of a guitar-shaped peripheral to simulate the playing of music, represented on-screen by colored notes that correspond to fret buttons on the controller. The games support both individual play, as well as cooperative and competitive modes for two players. The series has used a range of both licensed and independent rock music tracks from the 1960s to present, many of which are master tracks from the bands. In total, four games have been released for video game consoles, while one game has been released for mobile phones. Some upcoming games will also be released for the Nintendo DS handheld gaming system.