HTS heading 4810

Paper and paperboard, coated on one or both sides with kaolin (China clay) or other inorganic substances, with or without a binder, and with no other coating, whether or not surface-colored, surface-decorated or printed, in rolls or rectangular (including square) sheets, of any size — 93 codes under this heading, with the duty on each.

39 of these lines state no rate of their own and inherit one from the line above, which is how the schedule is read. Each says which line it came from.

Source: Harmonized Tariff Schedule of the United States, U.S. International Trade Commission (public domain). Classification and the duties that finally apply to a shipment are a licensed customs broker's call.