CBP generally applies the commercial designation used by the manufacturer, supported by size charts and labeling. Garments sized for boys (typically up to size 20 or equivalent) are classified under the boys' lines (e.g., 6101302020), while those sized for men fall under the men's lines (6101302010). Misclassification between men's and boys' lines can affect applicable textile category and quota monitoring, so importers should ensure size designations on commercial invoices and labels are consistent.

For garments claimed under the wool-blend line (6101301500, requiring ≥23% wool or fine animal hair) or the leather-content line (6101301000, requiring ≥25% leather), importers should obtain fiber/material content certifications from the manufacturer, ideally supported by laboratory test results. CBP may sample garments for fiber analysis at the port of entry, and discrepancies between declared and tested content can result in reclassification and additional duties.