5601 - Wadding of textile materials and articles thereof; textile fibers, not exceeding 5 mm in length (flock), textile dust and mill neps:

Heading 5601 encompasses wadding derived from textile materials and any articles manufactured from it. This category also includes very short textile fibers, specifically those not exceeding 5 millimeters in length, commonly referred to as flock, as well as textile dust and mill neps. The defining characteristic here is the form and short length of the textile material, often processed into a fluffy or fibrous mass.

This heading is distinct from other chapters within Section XI, particularly those dealing with yarns, fabrics, or finished textile articles. Unlike heading 5602 (Felt and felt-based nonwovens), which deals with matted fibers, heading 5601 focuses on loose fibers, wadding, and articles made from such wadding. It also differentiates from headings covering longer staple fibers or yarns which would be classified elsewhere based on their length and processing.

Within heading 5601, a key subdivision is found in subheading 5601.30.00.00, which specifically covers textile flock, dust, and mill neps. This further refines the classification by isolating these particularly fine or residual textile materials, which may be used as filling, insulation, or in other specialized applications distinct from the more organized wadding described in the broader part of the heading.