1PC N33 Round Magnet With Hole 25x10/15/20MM Hole 6MM NdFeB Magnetite Magnet. Grade: N33. 10PC Strong Magnets 30x5x2/3/5mm N33 grade neodymium block thin rectangle magnet. Neodymium iron boron magnetic material has higher hardness than ordinary materials and is less prone to rusting.
eBay