9902.01.30 - Amorphous silicon dioxide micro-spheres of mean particle size of 0.050-0.100 mm, and specific electrical resistance of 50,000 Ohm cm or more (CAS No. 7631-86-9) (provided for in subheading 2811.22.10)

This HTS classification, 9902.01.30, specifically covers amorphous silicon dioxide micro-spheres meeting precise physical and electrical resistance criteria. The defining characteristics are a mean particle size ranging from 0.050 to 0.100 millimeters and a specific electrical resistance of 50,000 Ohm cm or more. The CAS number 7631-86-9 is provided for definitive chemical identification. Crucially, this provision is established under Chapter 99 of the Harmonized Tariff Schedule, indicating it represents temporary legislation, temporary modifications related to trade agreements, or additional import restrictions enacted under Section 22 of the Agricultural Adjustment Act.

Given that Chapter 99 is dedicated to special and temporary provisions, this category is inherently distinct from the primary product chapters (01 through 98) which deal with the permanent classification of goods. Unlike typical HTS entries that define broad product categories, 9902.01.30 functions as a specific carve-out or modification to an underlying tariff classification. The parenthetical note "(provided for in subheading 2811.22.10)" clearly indicates that these micro-spheres would otherwise be classified under heading 2811.22 (Silicon dioxide) in Chapter 28, but are subject to the special provisions of Chapter 99. This highlights that the primary distinction lies in the *regulatory status* and *temporary nature* of the classification, rather than a fundamental difference in the physical product itself when compared to other entries in Chapter 99.

As this node represents a leaf node within the HTS database, there are no further subcategories for this specific classification. The detailed description, including particle size, electrical resistance, and the underlying permanent classification, fully defines the scope of goods covered. Classification under this provision is contingent upon meeting all the specified technical parameters, and its temporary nature necessitates careful monitoring of its expiration or amendment status.