Vevo and YouTube have started age rating music videos from three major record labels that may be unsuitable for children under 12. The BBFC classifies each video based on its guidelines for films, assigning a rating and content descriptors. Ratings of 12, 15, or 18 appear on the sites, denoting the level of language, nudity, violence, and other content in the video. Alternative rock music videos commonly feature drug use, sexuality, and sometimes violence, so they are usually not suitable for those under 12 or 15. Artists generally aim to keep ratings below 15 to maintain their audience size.