6903.90.00 - Other

This HTS category, "Other," encompasses refractory ceramic goods that do not fall under the more specific classifications within heading 6903. These goods are characterized by their ability to withstand high temperatures and chemical attack, making them suitable for use in industrial furnaces, kilns, and other high-heat applications. Examples include various components such as supports, plugs, tubes, and pipes, provided they are not primarily composed of siliceous fossil meals or similar siliceous earths.

To differentiate this category from its siblings, it is crucial to note the exclusion of goods containing specific material compositions. Unlike 6903.10.00.00, this category does not cover refractory ceramics with a free carbon content exceeding 50% by weight. Similarly, it excludes goods classified under 6903.20.00.00, which are characterized by a high alumina content (over 50% by weight) or a mixture of alumina and silica. This "Other" category serves as a residual for refractory ceramic articles that do not meet the criteria for these more specialized classifications.

Within this "Other" category, further distinctions are made to refine classification. Subcategories such as "Of clay" and "Other" provide for a more granular breakdown based on the primary material composition of the refractory ceramic goods. This allows for accurate classification of a wide array of refractory articles by specifying whether they are primarily derived from clay or from other ceramic materials not otherwise specified.