Magnet Expert F200F-20 10 x 5mm Isotropic Y30 Ferrite Magnet, 10 x 10 x 5mm Thick, Charcoal, 20 Each Set Pack of 20. 10mm [0.39"] x 10mm [0.39"] x 5mm [0.20"] square. Each magnet's north and south pole are on opposite square faces. Each magnet can support a steel weight of up to 0.08kg [0.17lb] vertically from the magnetic face when in flush contact with a mild steel surface. Resistant to demagnetisation and corrosion without any extra coating.