19 CFR §141.81
Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
A commercial invoice shall be presented for each shipment of merchandise at the time the entry summary is filed, subject to the conditions set forth in these regulations. Except in the case of installment shipments provided for in § 141.82, an invoice shall not represent more than one distinct shipment of merchandise by one consignor to one consignee by one vessel or conveyance.