Magnets 20x4 mm N35 Neodymium Disc very strong large round magnet 20mm dia x 4mm. Size:Diameter x Length +/- 0.3mm. Plating:Nickel-Copper-Nickel (NiCuNi) Triple Plating. Magnetisation Direction:Through the Thickness.
Please use caution and common sense, and please read and understand our safety warnings below! Keep Out Of Reach Of Children Under 14 Years Of Age. Although magnets can be wonderful toys and highly educational, these are'adult' toys, and NOT for children. Small children should not be allowed to handle any of our magnets at all! Older children should handle them only under adult supervision, and wearing proper safety equipment (depending on the size and power of the magnets being used).
Large magnets should be only be handled by adults with extreme caution. Small magnets could cause serious complications if swallowed - keep well away from children & pets. Pacemakers and defibrillators can be sensitive to strong magnetic fields. If you or someone in your household has a pacemaker or defibrillator, or has health issues which require that you wear electronics of any sort, avoid magnets completely until you consult your doctor!
Strong magnets can pose a serious pinch hazard due to their attractive force on each other and to any metal object containing iron. Usually surprise is an issue--they can jump out of your hands and snap together from a surprising distance before you realize what is happening. Though small magnets are quite safe in this respect, larger sizes are strong enough that they can pinch you like a pair of pliers or worse, and be very difficult to remove from your fingers without help.
They are strong enough that they can fly into each other or to a piece of iron or steel with such velocity that they can break and send sharp'shrapnel' flying about! Plus, your expensive magnets are then permanently broken. Glove may help prevent accidental blood blisters if the magnets snap together, but they may also compromise you firm grip.
Damage to magnetic storage media. Magnetic fields can cause damage to magnetic storage media. These include: cassette tapes, floppy disks, credit cards, video tapes, and computer hard drives. Keep all magnets at least 24 inches away from all types of magnetic media. Certain electronic devices are sensitive to magnetic fields and may be damaged permanently or temporarily disabled if exposed to a magnetic field that is too strong.Any CRT video screen or television will become distorted and/or discolored if exposed to a strong magnetic field. While damaged screens can usually be demagnetized, it's often tricky and may require qualified service technicians to do so. Other electronic devices like cellphones and pagers can also be damaged. Store your magnets in a safe place away from electronics of any kind. These magnets are by nature very hard and brittle.
Although they can be cut, drilled and machined, it should ONLY be done by folks who are experienced with ceramics. If the magnets get over about 300 deg F, they will lose their magnetism permanently. They are flammable, and it is not difficult while grinding or machining to get them (or the chips and dusts from cutting) so hot hot they ignite. If they do ignite, the fumes are toxic and the material burns very fast and hot, like Magnesium!
Please be careful and be safe!