9902.13.21 - Modacrylic staple fibers, not carded, combed or otherwise processed for spinning, containing over 35 percent and less than 85 percent by weight of acrylonitrile, 2.7 decitex (plus or minus 2 percent), natural in color, with fiber length between 38 mm and 120 mm (provided for in subheading 5503.30.00)

This HTS category, 9902.13.21, covers specific modacrylic staple fibers that are not yet ready for spinning. The core defining characteristics are their composition: containing more than 35 percent and less than 85 percent acrylonitrile by weight, a specific decitex of 2.7 (with a tolerance of 2 percent), natural coloration, and a defined fiber length between 38 mm and 120 mm. Crucially, these fibers are processed specifically for use within the textile industry and are provided for under subheading 5503.30.00, indicating their intended application and underlying material.

Given that this is a leaf node within Chapter 99, its classification is highly specific and does not have further subdivisions. Unlike the broader categories found at higher levels, such as live animals (0101-0105), this node deals with a niche industrial material. The temporary nature of Chapter 99 classifications means this specific provision is subject to change and likely relates to temporary trade agreements or import restrictions, as indicated by its context within Section XXII. Therefore, any goods falling under this classification must precisely meet all stated physical and compositional criteria to be correctly identified.