Magnetic hook Powerful magnet with attachment ring/Neodymium magnet with attachment key ring is super powerful. Magnetic hook magnet Magnet(NdFeB magnet) is made from Neodymium,Iron,Boron and someother ... : disc, cylinder, sphere, block ,ring ,tile, arc, and etc.High magnetic performance (Br: 11,000 to 14,500 Gs,Hci: 11 ... to 50MGOe )Maximum working temperature: 80 to 200 degrees C Magnetic hook