19 CFR 123.24 - Sealing of conveyances or compartments.
(a)Sealing required. Merchandise in transit proceeding under the provisions of this subpart shall be transported in sealed conveyances or compartments, except that:
(1) Less than load or compartment lots may be forwarded in unsealed conveyances or compartments, without cording and sealing;
(3) Live animals identifiable by specific description in the manifest may be transported in the care of an attendant or customs inspector at the expense of the parties in interest, in unsealed conveyances or compartments.
(b)Seals to be affixed. The carrier shall affix blue in-transit seals to all openings of conveyances and compartments containing in-transit merchandise except that:
(1) Sealable carload shipments on the Canadian border shall be sealed with yellow in-transit seals.
(2) Conveyances or compartments sealed with U.S. Customs red in-bound seals may go forward without additional seals.