These round ceramic discs are perfect for do-it-yourself projects like making your own magnets. Glue them to the back of any light to medium weight item and place on refrigerators, lockers, whiteboards, or any ferrous metal surface. Perfect for home, school, and office use, these hard ceramic ferrite magnets are composed of iron oxide and strontium carbonate. Ceramic magnets exhibit relatively good holding strength for their price, making them a popular choice for many consumer, commercial, and technical applications.