(Silicon dioxide amorphous) (CAS No. 7631–86–9) entirely spherical micro-spheres of mean particle size of 0.005 mm or smaller, uniform particle size with a uniformity coefficient of 1.65 or less, trace metal impurities less than 70 ppm, specific electrical resistance of 50,000 Ohm cm (provided for in subheading 2811.22.10) Free No change No change On or before 12/31/2020 . 29. Certain spherical particles of silicon dioxide Subchapter II of chapter 99 is amended by inserting in numerical sequence the following new heading: 9902.01.28 Dioxosilane (Silicon dioxide amorphous) (CAS No. 7631–86–9) presented in the form of entirely spherical micro-spheres, certified by the importer as having a mean particle size of between 0.046 and 0.054 mm, uniform particle size with a uniformity coefficient of 1.65 or less and specific electrical resistance of 50,000 Ohm cm or more (provided for in subheading 2811.22.10) Free No change No change On or before 12/31/2020 . 30. Certain spherical particles of silicon dioxide Subchapter II of chapter 99 is amended by inserting in numerical sequence the following new heading: 9902.01.29 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) Free No change No change On or before 12/31/2020 . 31. Certain spherical particles of silicon dioxide Subchapter II of chapter 99 is amended by inserting in numerical sequence the following new heading: 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) Free No change No change On or before 12/31/2020 . 32. Certain spherical particles of silicon dioxide Subchapter II of chapter 99 is amended by inserting in numerical sequence the following new heading: 9902.01.31 Amorphous silicon dioxide micro-spheres of