CBP and the HS notes look at whether the yarn is in small quantities, wound in a form suitable for individual consumer purchase (balls, skeins, small cones), and accompanied by consumer-facing labeling such as fiber content, care instructions, and weight. Large industrial cones or cheeses without retail labeling would not qualify, even if the same yarn composition is involved.

Because the combined wool and fine animal hair content is 100% but wool alone is 80% — below the 85% threshold — the yarn falls under 510990 (less than 85% wool or fine animal hair by weight). Note that the threshold applies to wool or fine animal hair combined, so if the 80% wool plus 20% cashmere totals 100% fine fiber, the classification still depends on how the schedule defines the threshold for this specific blend. Importers should consult the tariff schedule text and, if uncertain, seek a binding ruling.