19 C.F.R. § 123.7
When a shipment not exceeding $250 in value which is unconditionally free of duty and not subject to quota or to internal revenue tax arrives on a vessel of less than 5 net tons arriving otherwise than by sea, the inward foreign manifest on Customs Form 7533 may be presented in duplicate and used as an entry if:
[T.D. 70-121, 35 FR 8215, May 26, 1970, as amended by T.D. 73-175, 38 FR 17447, July 2, 1973]