The non-immigrant visa classification covers a broad range of visas used to enter the United States for work, pleasure or study. Some visas are considered 'dual status'; you may attempt to obtain permanent residency (a green card) while under that classification. Most non-immigrant visas, however, require you establish non-immigrant intent. Therefore, in such cases one must demonstrate that they have a permanent residence in their home country that they have no intention of abandoning. The duration of time that a beneficiary of a non-immigrant visa may spend in the U.S. can range from a few days to several years, depending on the visa. In most situations, the beneficiary's spouse and unmarried children under the age of 21 may accompany them on a derivative visa. Specific non-immigrant visas are as follows :