19 C.F.R. § 145.38 Diplomatic pouches.
Title 19 - Customs Duties
Mail articles bearing the official seal of a foreign government with which the United States has diplomatic relations, accompanied by certificates bearing such seal to the effect that they contain only official communications or documents, shall be admitted free of duty without Customs examination. [T.D. 73–135, 38 FR 13369, May 21, 1973, as amended by T.D. 78–102, 43 FR 14454, Apr. 6, 1978]
Title 19: Customs Duties
PART 145—MAIL IMPORTATIONS
Subpart D—Special Classes of Merchandise
§ 145.38 Diplomatic pouches.