Restricted (X 18+), or simply X, is one of the seven classification categories of the Australian film rating system.
X 18+ films are restricted to adults. It only contains content that is sexually explicit in nature. That is, material which shows actual sexual intercourse and other sexual activity between consenting adults. What is not permitted in X 18+ are depictions of sexual violence, coercion and "sexually assaultive" language.
Material that is classified X 18+ is forbidden from being sold or hired anywhere in the six states of Australia. Thus, they are available for sale or hire only in the Australian Capital Territory and the Northern Territory.