HTS code 9902.01.29 covers "Silicon dioxide amorphous, certified by the importer as comprising entirely spherical micro-spheres with mean particle size of 28 to 45 micrometers (µm) and surface area 600 to 800 m²/g (CAS No. 7631-86-9) (provided for in subheading 2811.22.10) " under the US Harmonized Tariff Schedule. This is the official duty rate charged by US Customs when this product is imported into the United States, sourced directly from the U.S. International Trade Commission and refreshed daily.