High-Temperature Resistant Circular Perforated Ferrite Permanent Magnet https://www.mlmagnet.com/product/ferrite-ring-shape-magnets/hightemperature-resistant-circular-perforated-ferrite-permanent-magnet.html This product is a high-temperature-resistant permanent magnet with a circular perforated surface. The material of the product is ferrite, which is a mixture of iron oxide and barium or strontium carbonate. It has good magnetic properties and can be widely used in modern electronics, especially in high-power motors and transformers. This is a High temperature resistant circular perforated ferrite permanent magnet. Each piece of the magnet is made with the later progressive technology and testing method. The magnets can be used in more applications in daily life, such as refrigerator doors.