19 CFR 147.2: Articles which may be entered for a fair.

(a) General. Any article imported or brought into the United States may be entered under bond under the regulations of this part for the purpose of exhibition at a fair, or for use in constructing, installing, or maintaining foreign exhibits at a fair, if no duty or internal revenue tax has been paid, and the article is:

(1) In a foreign-trade zone; or

(2) Imported for exhibition under Chapter 98, Subchapter XII, Harmonized Tariff Schedule of the United States; or

(3) In continuous Customs custody, including but not limited to articles:

(i) Imported or brought into the United States for the purpose of direct entry at a particular fair;

(ii) In Customs bonded warehouses;

(iii) Unentered under the Customs laws and held in general order pending entry or exportation;

(iv) On exhibition at another fair designated by the Secretary of Commerce.

(b) Exception. Articles which have been entered under Chapter 98, Subchapter XIII, HTSUS, may not be entered under the regulations of this part.