1604.14.22.91 - In foil or other flexible con- tainers weighing with their contents not more than 6.8 kg each

This HTS classification specifically covers prepared or preserved tuna and skipjack tuna, packed in airtight containers, but not in oil. The defining characteristic for inclusion in this category is the weight of the container and its contents, which must not exceed 6.8 kilograms each. These products are typically found in foil or other flexible packaging, distinguishing them from goods in rigid cans or jars.

This category is distinct from its sibling, 1604.14.22.99, which encompasses "Other" tuna and skipjack in airtight containers not in oil, when these criteria are not met. The primary differentiator is the precise weight limit of the flexible container and its contents.

As this HTS code is a leaf node, there are no further subcategories. Therefore, classification into this code is definitive based on the outlined product characteristics: tuna or skipjack, prepared and preserved, in airtight flexible containers weighing with their contents not more than 6.8 kg each, and not packed in oil.