Edible animal casings must come from USDA FSIS-approved foreign establishments and are subject to reinspection at the US port of entry. The exporting country must have an equivalent meat inspection system recognized by FSIS. Inedible casings destined for non-food industrial uses follow a different admissibility path and may not require FSIS oversight, though CBP entry requirements still apply.

Guts, bladders, and stomachs classified here include whole pieces regardless of whether they are fresh, chilled, frozen, salted, or dried, as long as they remain in a form that has not been further manufactured into a finished product. Processed or prepared casings that have been stuffed, formed, or otherwise converted may advance to a different heading depending on the degree of processing.