1/2/5pcs 50x5mm Super Powerful Strong Magnetic Ndfeb 50mmx5mm N35 Permanent Neodymium Magnets 50x5 Mm Big Round Magnet 50*5 Mm - Magnetic Materials - AliExpress
Rare-earth magnet - Wikipedia
Strong powerful block magnet 50mm permanent neodymium magnets magnetic materials - China Neodymium Magnet and Permanent Magnet