19 C.F.R. § 141.33
An individual (but not a partnership, association, or corporation) who is not a regular importer may appoint another individual as his unpaid agent for Customs purposes by executing a power of attorney applicable to a single noncommercial shipment by writing, printing, or stamping on the invoice, or on a separate paper attached thereto, the following statement:
__________________________; of
(Name)
_______________________________
(Address)
is hereby authorized to execute, as an unpaid agent who has knowledge of the facts, pursuant to the provisions of section 485(f), Tariff Act of 1930, as amended, the consignee's and owner's declarations provided for in section 485 (a) and (d), Tariff Act of 1930, as amended, and to enter on my behalf or for my account the goods described in the attached invoice which contains a true and complete statement of the facts concerning the shipment.
Date __________________, 19____.
(Signature of importer)
(Address)
19 C.F.R. §141.33