Duty free tariff preference scheme for least developed countries: rules on determining origin, certification, and verification for preferential import duties. Products qualify for preferential tariff treatment if they are originating products, either wholly obtained in the beneficiary country or meeting origin tests: non originating materials must not exceed 70% of FOB or ex works value (minimum 30% local value added), there must be an applicable 6 digit HS classification change, and final manufacture must occur in the beneficiary country. The scheme requires direct consignment, a standardized certificate of origin issued by a notified authority, specified documentary evidence, retention of records for five years, and provides procedures for retroactive checks, verification visits, denial and suspension of preferences for non compliance or fraud.