An adult rating is a type of rating that, when applied to a film, video game, or other form of media, restricts its viewing audience to persons aged 18 years or over. The X rating from the MPAA was a famous adult rating, due to it being used by the pornography industry as an advertising gimmick and, as a result, films with that rating being mistaken as pornographic in material. 18 is a very commonly and frequently used age restriction on an adult rating. The BBFC's 18 certificate is also used as an adult rating. Adult ratings may be fully restricted, as a stopgap measure to keep underage viewers from seeing graphic violence, very explicit language, pornography, or any other strong material that most parents would find unsuitable for their children 17 and under. Children generally are not admitted to an adult-rated motion picture under any circumstance. A few R-rated movies may count as adult pictures, especially during the later years, when the occurance of softcore pornography became more accepted in films with that rating.