A sex offener is a person who has been criminally charged and convicted of, or has pled guilty to, or pled Nolo contendere to a sex crime. Crimes requiring mandatory sex offender registration may include downloading pornographic material of persons under the age of 18, (child pornography), rape, statutory rape and even non-sexual offenses such as kidnapping. The term sexual offender is a broad term, with sexual predator being used to describe a more severe physical or repeat sexual offense. Sexual offenders are also sometimes classified into levels , where the highest level offenders have the most aggravating crimes and thus, the most risk to the public and usually must register as a sex offender for their entire lives. Low level sexual offenders may serve only a probationary sentence and only register for 10 years as well as having less restrictions placed on them compared to higher level offenders. As a label of identity it is used in criminal psychology. Especially in the United States and the United Kingdom, the person, if convicted, is most likely required to register with the respective jurisdiction's sex offender registry, a county- or statewide database that is often public and accessible to everyone through the internet.