Super Strong Neodymium Magnet N42 3 x 1/2 x 1/8" Permanent Magnet Bar, The World's Strongest & Most Powerful Rare Earth Magnets by Applied Magnets: Amazon.com: Industrial & Scientific
N42 Neodymium Rectangular Magnet - 2.5mm x 7mm x 2.5mm thick - 0.88lbs Pull