7209.18 - Of a thickness of less than 0.5 mm:

This HTS category, 7209.18, specifically covers flat-rolled products of iron or non-alloy steel that have been cold-rolled (cold-reduced) and are at least 600 mm in width. The defining characteristic of this subcategory is its thickness, which is precisely less than 0.5 mm. These products are supplied in coils and have not undergone any further working beyond the cold-rolling process, nor are they clad, plated, or coated with other materials.

Distinguishing this category from its siblings is crucial for accurate classification. While all fall under the umbrella of cold-rolled flat-rolled products in coils, 7209.18 differs based on thickness. Sibling categories 7209.15, 7209.16, and 7209.17 address thicker materials ranging from 0.5 mm upwards. Therefore, any product falling under 7209.18 must be thinner than 0.5 mm, making it distinct from these slightly thicker counterparts.

Within the 7209.18 classification, further distinctions are made to provide more granular detail. The subcategories 7209.18.15 and the "Other" category allow for the segregation of high-strength steel products from other types of steel within this specific thickness range. This differentiation is important for trade statistics and potentially for applying specific duties or regulations that may be associated with different grades or performance characteristics of steel.