HTS code 9902.13.31 covers "Artificial staple fibers, not carded, combed or otherwise processed for spinning, of viscose rayon, containing between 28 percent and 33 percent by weight of silica, measuring 5.0 decitex in lengths of 60 mm (provided for in subheading 5504.10.00)" 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.