An importer who wishes to claim preferential tariff treatment for his goods is required to specify his intention to do so in the TradeNet declaration for his In-Payment Permit by leaving the "Customs Duty Rate" field blank and indicating "PRF" in the "Preferential Indicator" field. He is required to declare the excise duty rate of the goods accordingly in the declaration. The importer is to submit the certification of origin (i.e., Form E issued by China), duly-declared In-Payment Permit, commercial invoice, bill of lading (B/L) and other relevant documents to Singapore Customs within one week of the release of the goods from the Customs checkpoint for our verification. If the certification of origin is not submitted to us within the stipulated period, we will proceed with duty recovery.