A shirt whose chief weight fiber is polyester (55%) would classify under the non-cotton woven shirt heading rather than the cotton shirt heading, because classification follows the predominant fiber by weight. This distinction matters because the two headings carry different duty rates. Importers of blended-fabric shirts should confirm fiber percentages through lab testing and declare the chief-weight fiber accurately on entry documentation.

The core documentation requirements — commercial invoice with fiber content, country of origin, HTS classification, and FTC-compliant labeling — apply equally to linen and silk shirts. However, silk shirts may attract additional scrutiny regarding fiber content verification given the value differential between genuine silk and synthetic alternatives. For high-value silk shipments, a fiber content certificate from an accredited laboratory is advisable to support the declared classification and value.