6203.31.50.10 - For suits described in Note 3(a) (443)

This HTS category, 6203.31.50.10, specifically classifies men's or boys' suit-type jackets and blazers that are constructed from worsted wool fabric. A key defining characteristic for inclusion in this subcategory is that the wool yarn used in the fabric must have an average fiber diameter of 18.5 microns or less. This precise measurement of fiber fineness is crucial for distinguishing these garments from others made with coarser wools.

The distinction from its sibling category, 6203.31.50.20, lies solely in the specification of the wool yarn's fiber diameter. While both categories fall under "Of wool or fine animal hair" and "Of worsted wool fabric," this particular node isolates garments made with exceptionally fine worsted wool, often associated with higher quality and a smoother finish. The "Other" category would encompass worsted wool jackets and blazers not meeting this specific micron requirement.

As this is a leaf node within the HTS structure, there are no further subcategories for this specific classification. Therefore, the focus is on the direct application of the criteria: the garment must be a suit-type jacket or blazer, made of worsted wool fabric, and crafted from wool yarn with an average fiber diameter of 18.5 microns or less. Importers should ensure their documentation clearly supports this material specification for accurate classification.