9902.14.69 - Polycrystalline fibers containing by weight over 70 percent of alumina and less than 30 percent of silica, the foregoing containing no alkaline oxides or boric oxide, presented in bulk (provided for in subheading 6806.10.00)

This HTS category, 9902.14.69, specifically covers polycrystalline fibers with a high alumina content, exceeding 70% by weight, and a limited silica content, less than 30%. Crucially, these fibers must be free from alkaline oxides and boric oxide, and are presented in bulk form. This classification falls under the special provisions of Section XXII, indicating that it is subject to temporary legislation or modifications, often related to trade agreements or agricultural import restrictions.

Given that this is a leaf node within the HTS, there are no further subcategories to explore. Instead, the focus is on clearly identifying the precise material composition and presentation to ensure accurate classification. It is important to distinguish this category from other HTS provisions that might cover fibers or refractory materials, as the specific percentage limitations for alumina and silica, combined with the absence of alkaline and boric oxides, are the defining criteria. The reference to "provided for in subheading 6806.10.00" in the description clarifies that while the material itself may have a principal classification elsewhere, this 9902 code applies a special provision, likely a temporary modification to tariff or import requirements.