19 C.F.R. § 102.25

In connection with a claim for NAFTA preferential tariff treatment involving non-originating textile or apparel products subject to the tariff preference level provisions of appendix 6.B to Annex 300-B of the NAFTA and Additional U.S. Notes 3 through 6 to Section XI, Harmonized Tariff Schedule of the United States, the importer must submit to CBP a Certificate of Eligibility, or its electronic equivalent, covering the products. The Certificate of Eligibility, or its electronic equivalent, must be properly completed and signed by an authorized official of the Canadian or Mexican government and must be presented to CBP at the time the claim for preferential tariff treatment is filed under § 181.21 of this chapter. If the Center director is unable to determine the country of origin of the products, they will not be entitled to preferential tariff treatment or any other benefit under the NAFTA for which they would otherwise be eligible.