5603.94 - Weighing more than 150 g/m2:

This HTS subcategory, 5603.94, specifically covers nonwoven textile materials, whether or not they have undergone processes like impregnation, coating, covering, or lamination, that weigh more than 150 grams per square meter (g/m²). These are distinct from other "Other" nonwoven classifications within 5603.9 which are defined by lighter weight thresholds.

The crucial differentiator for 5603.94 is its weight requirement. Unlike its siblings 5603.91, 5603.92, and 5603.93, which cover nonwovens weighing up to 150 g/m², this category applies to only the heaviest nonwoven materials within the "Other" group. This weight distinction is a primary factor for customs classification, often indicating a more substantial or durable product.

Within 5603.94, further subdivisions exist to refine classification based on end-use and specific composition. One such subdivision is for floor covering underlays, highlighting a common application for these heavier nonwovens. The "Other" subcategory serves as a catch-all for any remaining nonwoven materials meeting the weight criteria but not fitting into the more specific end-use categories.