5403.10 - High tenacity yarn of viscose rayon:

This HTS category, 5403.10, specifically pertains to high tenacity yarns manufactured from viscose rayon. High tenacity yarns are characterized by their superior tensile strength and lower elongation compared to standard yarns, making them suitable for applications requiring durability and resistance. Viscose rayon is a regenerated cellulosic fiber, meaning it is derived from wood pulp or other plant-based materials. The "not put up for retail sale" clause within the parent category indicates these yarns are typically supplied in bulk for industrial use rather than packaged for consumer purchase.

Within the broader context of artificial filament yarn, this category differentiates itself from its siblings by its specific material (viscose rayon) and its high tenacity characteristic. The sibling categories, "Other yarn, single" and "Other yarn, multiple (folded) or cabled," likely encompass a wider range of artificial filament yarns that do not meet the high tenacity criteria or are not of viscose rayon origin, and also include distinctions based on yarn construction.

The subcategories under 5403.10 further refine the classification based on the yarn's construction. Subcategory 5403.10.30 classifies single yarns, which consist of a single strand of filament. In contrast, subcategory 5403.10.60.00, often indicated by a "(606)" designation, is reserved for multiple (folded) or cabled yarns, where two or more single yarns are twisted together. This distinction is crucial for accurate customs reporting and duty assessment.