Duty Entitlement Pass Book Scrip exemption for customs and additional duty conditioned on permitted credits and valid ports of use. Exemption is provided for specified imported goods from Customs duty and additional duty when imported against a Duty Entitlement Pass Book Scrip, subject to conditions: the importer must hold a DEPB Scrip issued by the Licensing Authority with permitted credit entries at government-notified rates; the DEPB Scrip must be produced for debiting duties that would otherwise be leviable and must have sufficient credit; the DEPB Scrip is valid for twenty four months (subject to extension) and use is limited to listed ports, airports, ICDs, land customs stations or SEZs, with Commissioner of Customs able to permit other locations.