19 CFR § 123.4 - Inward foreign manifest forms to be used.
The inward foreign manifest required by § 123.3 for a vehicle or a vessel of less than 5 net tons arriving in the United States from Canada or Mexico otherwise than by sea with baggage or merchandise, must be on CBP Form 7533, except as provided for shipments in transit in subparts C, D, E, F, and G of this part, and in the following special cases:
(b) For dutiable merchandise not exceeding $2,500 in value entered on CBP Form 368 or 368A, (serially numbered) or CBP Form 7501, or its electronic equivalent, the same form may be used as a manifest in lieu of other forms. (See § 143.21 of this chapter.) The port director may also allow such merchandise to be entered informally upon the presentation of a commercial invoice which contains the following declaration, signed by the importer or his agent:
I declare that the information on this invoice is accurate to the best of my knowledge and belief; that the invoice quantities are true and correct manifest quantities; and that I have not received and do not know of any invoice other than this one.
(c) For a shipment not exceeding $250 in value consisting of articles of American origin entered free of duty under the provisions of § 10.1(i) of this chapter and imported in a vehicle, CBP Form 3311, or its electronic equivalent, used in entering the goods, in duplicate, may be accepted in lieu of a manifest.