Subject to the more specific explanations of the criteria in §§ 10.303 and 10.305 of this part, goods classifiable under an HTSUS heading or subheading for which the symbol “CA” appears in the “special” column are eligible for a preference if:

(a) Originating goods. The goods originate in Canada or the United States, or both, and

(b) Direct shipment required. Except as provided in § 10.306(b), are directly shipped to the United States from Canada.