The round ring ferrite permanent magnet is a ferrite that can be mounted on any surface to form a permanent magnet. The magnetic field increases the number of applications this ferrite magnet gives you the strength and stability required in hard drives, motors, and other static-sensitive electronics. [email protected] The round ring ferrite permanent magnet is a ferrite that can be mounted on any surface to form a permanent magnet. The magnetic field increases the number of applications this ferrite magnet gives you the strength and stability required in hard drives, motors, and other static-sensitive electronics. [email protected] https://www.mlmagnet.com/product/ferrite-ring-shape-magnets/round-ring-ferrite-large-ferrite-permanent-magnet.html