Descriptions: 1Pc N52 40x40x20mm Neodymium Magnet Strong Powerful Block Magnets Rare Earth Imanes. Specifications: Shape:Block; Color:Silver; Material:Neodymium Magnets; Max Operating Temperature:80°C/176°F; Max Magnetic pull force:ca. 60kg (The long and wide sides are the front of the magnetic pole); (The pull force was tested at 20 Celsius degree, on a polished iron plate with a thickness of 20 mm. The magnet was deducted vertically. A difference of up to -10% compared to the specified value is possible in exceptional cases.); Grade:N52, N40, N35; Size(L x W x Thickness):40 x 40 x 20mm, 37 x 37 x 17mm, 50 x 25 x 10mm; Tolerance:+-1.5mm. Features: - Great for DIY, science projects, holding, stud finders, locating nails under floor. - They are hard to separate once they get attracted with each other. It's perfect for wind generators. - It's perfect for screws collection. Caution: - Strong magnets are brittle; - Strong magnet could pinch your fingers badly; - If you allow two magnets attract together, it may cracks and the chips could hurt your eyes. Package Included: 1 Pc x Strong Block Neodymium Magnet(Coins NOT INCLUDED )