4823.20 - Filter paper and paperboard:

This HTS category, 4823.20, specifically encompasses filter paper and paperboard. These are characterized by their porous structure, designed to allow the passage of fluids or gases while retaining solid particles. This often involves specific manufacturing processes, such as controlled fiber formation or the introduction of pore-generating agents, to achieve the desired filtration properties. Examples include paper used in laboratory filtration, industrial separators, and various consumer applications requiring purification or separation.

When differentiating from sibling categories at the same level, it's important to note that this heading focuses exclusively on the filtration function. For instance, while other products like printed rolls (4823.40) or molded articles (4823.70) are also made from paper or paperboard, their primary purpose is not filtration. Similarly, the general "Other" category (4823.90) would not apply to items designed and manufactured for their filtering capabilities.

Within the 4823.20 heading, two primary subcategories exist to further refine classification. Subcategory 4823.20.10.00 specifically covers paint filters and strainers, highlighting their application in the automotive, industrial, or consumer painting processes. The broader subcategory, 4823.20.90.00, serves as a residual for all other filter paper and paperboard not specifically enumerated, ensuring comprehensive coverage for the diverse range of filtration media falling under this general description.