Certificates provide ratings to indicate the appropriate age for viewing films. The 'U' rating means a film is suitable for all ages and will contain no inappropriate content. The 'PG' rating recommends parental guidance as some scenes may not be suitable for children. Films rated '12A' can contain stronger violence but not too strongly as the target age is still young. A '12' rating means no one under 12 can view without a parent present and films may contain mild language. '15' rated films are unsuitable for those under 15 and can contain strong language, sexual content and violence. The most restrictive '18' rating designates adult films that contain explicit content and require proof of age to view.