9902.13.09 - Modacrylic staple fibers containing 35 percent or more but not over 85 percent by weight of acrylonitrile units and 2 percent or more but not over 3 percent of water, not pigmented (ecru), crimped, with an average decitex of 1.7 (plus or minus 10 percent) and fiber length of 51 mm (plus or minus 10 percent) (provided for in subheading 5503.30.00)

This HTS classification, 9902.13.09, pertains to a very specific type of modacrylic staple fiber. These fibers are characterized by a significant acrylonitrile content, ranging from 35% to 85% by weight. Further defining features include a controlled water content (2% to 3%), an uncolored state (ecru), and a crimped texture. Crucially, the fibers must meet precise physical specifications: an average decitex within 1.7 (plus or minus 10%) and a fiber length of 51 mm (plus or minus 10%). This provision is made under Section XXII, specifically addressing temporary legislation and modifications, and its base classification is found under subheading 5503.30.00.

Given its placement within Chapter 99, this category functions as a temporary modification or special provision rather than a primary classification of goods. Therefore, direct comparison to sibling categories in Chapters 1-98 is less relevant. Instead, its distinctiveness lies in its specific technical parameters and its temporary nature. It is important to note that this is a leaf node, meaning there are no further subdivisions. Classification under 9902.13.09 is exclusive to modacrylic staple fibers meeting *all* the detailed criteria outlined in the description, including the precise acrylonitrile content, water percentage, color, crimp, decitex, and fiber length. Any deviation from these exact specifications would necessitate classification under a different HTS code.