Rules of Origin verification: importers must declare origin, retain Form I evidence and comply with document requests promptly. Importers claiming preferential rates must declare goods as originating, cite the tariff notification, produce Certificates of Origin and enter CoO details in the bill of entry, and possess and retain Form I information demonstrating compliance with origin criteria including regional value content and product specific rules. Proper officers may requisition these documents, requiring a ten working day response; if satisfied, acceptance must be communicated within fifteen working days, otherwise a verification proposal is forwarded. Importers must exercise reasonable care in accuracy and retain supporting documents for five years.