Super Strong N52 Neodymium Magnet 4 x 1/2 x 1/4" Bar, The World's Strongest & Most Powerful Rare Earth Magnets by Applied Magnets: Amazon.com: Industrial & Scientific
DIYMAG 40x20mm Super Strong Neodymium Disc Magnet, Permanent Magnet Disc, The World's Strongest and Most Powerful Rare Earth Magnets - One Piece: Amazon.com: Industrial & Scientific