6907.21.90.51 - Other

This classification covers ceramic tiles and similar articles used for flags, paving, hearths, and walls, which are not specifically categorized under subheadings 6907.30 or 6907.40. The key defining characteristic is their very low water absorption rate, not exceeding 0.5% by weight. This indicates a dense, vitrified ceramic material, making these tiles highly resistant to moisture and staining, suitable for demanding applications.

Within the "Glazed" category at this level, 6907.21.90.51 specifically designates items that are not classified as "Tiles, the largest surface area of which is capable of being enclosed in a square the side of which is 30 cm or less" (6907.21.90.11). Therefore, this subheading applies to glazed, low-absorption ceramic tiles and similar articles that exceed these specific dimensional criteria, such as larger format tiles or custom shapes.

As this is a leaf node in the HTS, there are no further subcategories under 6907.21.90.51. Classification is determined by the absence of the specific tile dimensions found in its sibling category.