Neodymium Disc Magnet 4 x 2.5 mm N35
 
Neodymium (NdFeB) is among the strongest magnetic materials, even in small sizes, and its stability makes it useful for many practical applications. Compared with conventional ferrite magnets, neodymium provides much greater magnetic attraction. A protective coating helps improve durability. N35 indicates the magnetic grade; a higher number generally means a stronger magnet, with NdFeB grades commonly ranging from N35 to N52.
 
This very small size is often used in electronics, sensors, model making, prototypes and precision mechanics where an unobtrusive attachment is required. Even a small gap caused by thick paint, tape or an uneven surface noticeably reduces holding force. It performs best on solid steel.
 
Warning: keep away from children. Two magnets can snap together quickly, pinch fingers and crack or chip. Use spacers for storage and take care when separating them. Keep them away from sensitive electronics, cards and medical devices.