Heavy Duty Magnets: Made of neodymium material, the magnetism is much stronger than the usual refrigerator magnets, and after testing, each strong fridge magnet can easily support 15 sheets of A4 paper. Perfect Size: Each office magnets measures 0.47x0.63 inches, and they're small so they don't obscure exactly what you want to display. And the pushpin shape is easy to hold again. Wide Applications : Whiteboards, refrigerators, lockers, bulletin boards, food sealing, duty rosters, etc. are all arenas where strong fridge magnets can be used to their fullest potential. Ideal for home, school, shop, warehouse, retail and office. Not suitable for glass whiteboards Scratch and Rust Resistant Whiteboard magnets are plated with a triple protective coating (nickel + copper + nickel) and have a polished surface that greatly protects your refrigerator from scratches and rust.