Mainstream rock is a radio format. It is used by many commercial radio stations in the United States and Canada. It is also known as heritage rock. Mainstream rock stations represent the middle ground between classic rock and active rock on the programming band. They perform a balanced airplay of tracks found on active rock and classic rock playlists. But the music playlist has a tendency to focus on mapping hard rock music from the 1970s through the 2000s. Outside the United States and Canada, mainstream rock refers generally to rock music, which is considered as "radio friendly". It very rarely is referred to as a specific radio format.