Check the listing for details. 8mm x 3mm 5/16x1/8" N52 Super Strong Rare Earth Neodymium Magnet Disc 8x3mm. Width: 1/8 inch, Condition: New. Listed at 15.50 USD. 8mm x 3mm Super Strong Round Magnets Rare Earth Crafts Fridge Magnets Specification:Dimensions: 8mm x 3mm thick (5/16" x1/3" thick) Tolerances: ±0.2mm x ±0.2mm (0.01in) Plating/Coating: Ni-Cu-Ni (Nickel) Magnetization Direction: Axial (Poles on Flat Ends) Max Operating Temp: 176ºF (80ºC) Material Features:N52 grade Magnets are made of a brittle material. These magnets are not as strong as steel. They are more like a brittle ceramic. If you let two magnets slam together, they can crack and break. This is true for magnets large and small. WARNING!!! Strong magnets should Keep away from Ironware and some easily magnetized iron products, such as monitors, bank cards, computers, televisions, mobile phones and other. These magnets are very powerful which should be handled with great care. Without parents supervised do not allow children to playing magnets as they could get injured. Especially pay attention to the small magnets, please place in somewhere children can't reach place.8mm x 3mm Super Strong Round Magnets Rare Earth Crafts Fridge Magnets Specification:Dimensions: 8mm x 3mm thick (5/16" x1/3" thick) Tolerances: ±0.2mm x ±0.2mm (0.01in) Plating/Coating: Ni-Cu-Ni (Nickel) Magnetization Direction: Axial (Poles on Flat Ends) Max Operating Temp: 176ºF (80ºC) Material Features:N52 grade Magnets are made of a brittle material. These magnets are not as strong as steel. They are more like a brittle ceramic. If you let two magnets slam together, they can crack and break. This is true for magnets large and small. WARNING!!! Strong magnets should Keep away from Ironware and some easily magnetized iron products, such as monitors, bank cards, computers, televisions, mobile phones and other. These magnets are very powerful which should be handled with great care. Without parents supervised do not allow children to playing magnets as they could get injured. Especially pay attention to the small magnets, please place in somewhere children can't reach place.