HTS code 6902.10.50.00 covers "Refractory bricks, blocks, tiles and similar refractory ceramic constructional goods, other than those of siliceous fossil meals or similar siliceous earths › Containing by weight, singly or together, more than 50 percent of the elements magnesium, calcium or chromium, expressed as MgO, CaO or Cr2O3 › Other" 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.