1604.14.22.51 - In foil or other flexible con- tainers weighing with their contents not more than 6.8 kg each

This HTS classification applies to specific types of prepared and preserved fish, namely albacore tuna, packed in airtight containers that are not in oil. The defining characteristic of this category is the packaging: it encompasses products presented in foil or other flexible containers, where the combined weight of the container and its contents does not exceed 6.8 kg. This meticulous weight stipulation is crucial for accurate classification.

This category is distinguished from its sibling, 1604.14.22.59 "Other," by the specific requirement for flexible packaging. While both may contain albacore tuna in airtight containers and not in oil, the "Other" category would encompass alternative packaging formats not meeting the flexible container and weight criteria. The current category is a leaf node, meaning it has no further subdivisions. Therefore, classification at this level is definitive based on the product being albacore tuna, presented in flexible airtight containers not exceeding 6.8 kg with contents.