Sintered neodymium-iron-boron (NdFeB) magnets are metallic permanent magnets classified under 850511. Bonded or polymer-matrix rare-earth magnets may fall under 850519 (non-metallic permanent magnets) depending on their composition. The distinction turns on whether the magnet matrix is predominantly metallic or non-metallic.

Magnetic separators are generally classified under heading 8479 (machines for specific industrial processes) rather than 8505, because their principal function is separation rather than holding or coupling. The electromagnets or permanent magnets inside such a separator, if imported separately as components, could fall under 8505, but the complete separator unit is assessed by its function.