Permanent: Planted with triple plating layers (nickel + copper + nickel), which was developed to be the excellent protection to protect the magnet from rust and offers a shiny. Widely used : These Rectangular Neodymium Magnets Set Each piece of magnet holds more than 33 lbs in weight is widely used as a fridge magnet magnet, sign, note or picture holder, hardware tools hanger, artwork and craft DIY material. Magnet dimensions: 60 mm x 10 mm x 4 mm (approx.2.36 "x 0.4" x 0.2 ").Tolerances: 0.2 mm x 0.2 mm. Top quality: Manufactured under ISO 9001 quality systems. ATTENTION: Neodymium magnet is fragile, please do not hit it with force. How do you use the magnet safely? 1.Slide ONE magnet at the top of the chimney. 2.Once the stack, carefully start lifting the magnet. 3.Lift the magnet to rid yourself of the pile. Warning 1.These magnets are very powerful which should be treated with great care.Do not allow children to play with them Without supervision as they might pay attention to the samll magnets get injured.Especially, please sit in somewhere children can't reach 2.Care should be used when handling two magnets as they are together with such force pull, parts of the magnets may chip and cause injury.Keep magnets away from magnetic storage media such as cell phones, bank cards and computers.