N42 Neodymium Ring Magnet - 3/4 in. dia x 1/4 in. thick x 11/32 in. hole - 17.86lbs Pull

• 19.1mm outer diameter x 9.5mm inner diameter x 6.4mm thick.
• 0.75 in. outer diameter x 0.37 in. inner diameter x 0.25 in. thick.
• Each magnet's north and south pole are on opposite circular faces.
• Excellent resistance to demagnetisation.
• Each magnet is coated with three layers of nickel, copper and nickel to improve corrosion resistance 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 9mm (0.35 in.) copper pipe. 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. Compare this with an unmagnetised ring of the same dimension by repeating and watch as the unmagnetised ring slides down the pipe in an instant. A great way to bring magnets to life in the classroom.