40mm O.D x 25mm I.D x 5mm thick Neodymium Magnet - 20kg Pull

• 40mm outer diameter x 25mm inner diameter x 5mm thick.
• Each magnet's north and south pole are on opposite circular faces.
• Each magnet can support a steel weight of up to 20kg vertically from the magnetic face when in flush contact with a mild steel surface.
• Excellent resistance to demagnetisation.
• Coated with three layers of nickel, copper and nickel to reduce corrosion and provide a smooth and clean finish.

These versatile high-performance ring magnets, with north and south poles on opposing circular faces, have many uses. They are used in many everyday appliances such as vacuum cleaners plus motors, generators, rotor shafts and more. They can even be used to demonstrate intriguing 'eddy currents' using a copper pipe slightly thinner than the magnets inner diameter. Simply slide the ring over the pipe and let it slide down its length and watch it slowly descend as the eddy currents produced create a damping effect. A great way to bring magnets to life in the classroom.