These cone magnets are neodymium magnets with special features.
The magnetic flux lines are bundled on the small circular surface, and therefore the magnets possess a strong adhesive force.
10 mm magnets possess of over 1 kg adhesive force.
15 mm magnets possess of over 3 kg adhesive force.
20 mm magnets possess of over 5 kg adhesive force.
25 mm magnets possess of over 9 kg adhesive force.
The north pole is located on the small circular surface.