Ferrite is a ceramic material made by mixing Iron3oxide and Strontium. Ferrite is the world's most manufactured magnets, one reason for this is due to the low price. The ferrite material has a max working temp. of 250 °C. See our magnets facts page for more information about ferrite and the other magnet materials. If you don't find the size you are looking for, don't hesitate to contact us. We can make almost any size and shape after your demands. In fact, most of our standard-stock is once up on a time a customer size request.