Any article imported or brought into the United States—

(1) which is in continuous customs custody, covered by a customs exhibition bond, or in a foreign trade zone, and

(2) on which no duty or internal-revenue tax has been paid,

may, without payment of any duty or internal-revenue tax, be entered under bond under this section for the purpose of exhibition at a fair, or for use in constructing, installing, or maintaining foreign exhibits at a fair.