DescriptionWith Holes : NoApplication : Industrial MagnetComposite : Rare Earth MagnetModel Number : imanesShape : BlockType : PermanentOrigin : Mainland ChinaCertification : NONEMaterial: Neodymium Magnets Certification:RoHS passed Grade: N35 Magnetization: Axially magnetized / Poles on Flat Ends Condition: Brand new Shape: Block Tolerance: +-1-3 mm Dimension: 40mm*20mm*3mmDescription Tolerance:+-(1mm-5mm) Neodymium (chemical symbol Nd) is element 60 on the periodic table. It is a rare earth metal and forms one of the Lanthanides series. When added to Iron (Fe) and Boron (B) (chemical formula Nd14Fe21B) the resultant magnets are the strongest magnets currently available. Neodymium magnets are sometimes known as Neo,Neod or NIB magnets. Neodymium magnets are usually coated Nickel-Copper-Nickel plating to prevent the iron from rusting. Neodymium block magnet was made of NdFeB, have strong magnetic performances and appearance does not rust, usually placed in room temperature, the maximum operating temperature is 80 C ,and it never will demagnetization.Note:1: Neodymium magnet is extremely powerful, pls take care of your fingers or other body parts to avoid injured between 2 pieces big magnet2: Neodymium magnet is very fragile & easy damaged, pls handle gently The. Strong magnets is made of rare earth at high temperature, and it is impossible to guarantee 100% perfection. Its small flaws will not affect its performance and use.3: Strong magnets should keep away from ironware and some easily magnetized iron products, such as monitors, bank cards, computers, televisions and mobile phones4:Prohibit contact and use by children under 8 years old, prevent children from swallowing