Floor cores of fiberboard sold as a component of floors, not of metal; Floor cores of fiberboard sold as a component of engineered wood floors in the nature of boards; Floor cores of fiberboard sold as a component of non-metal floors comprised of a wood veneer and a core in the nature of fiberboard for multiple layer floor coverings; Floor cores of fiberboard sold as a component of non-metal floors comprised of wood veneer and cores of fiberboard for multiple layer floor coverings