In 1985, a Senate hearing was instigated by the Parents Music Resource Center (PMRC), who wanted to introduce a parental warning system that would label all albums containing offensive material. The system was to include letters identifying the type of objectionable content to be found in each album (e.g. O for occult themes, S for sex, D for drugs, V for violence, etc.). Dee Snider, John Denver, and Frank Zappa all testified against censorship and the proposed warning system. Such a system was never implemented, but the result of the hearing brought about what is now the generic "Parental Advisory: Explicit Content" label.