Ring magnets, include ring magnet and tube magnet, round magnets diameter goes commonly up to 145mm with either neodymium magnet material, ceramic magnet(ferrite) material, and Alnico magnet material. There is an evenly hollow threaded holes on the center for secure mating, that’s why it calls ring magnets.

Ring magnets can be used for medical equipment, jewelry, crafts, bearings, high-end speakers, magnetic levitation displays, electric motors, pumps, vacuum cleaners, magnetic experiments, sensor, and so on. Most of these ring-shaped magnets are axially magnetized with requirement of a certain height/thickness, such as 10mm diameter and 5mm thickness. Ring magnets with countersunk holes is also an alternative option from here.

Magsafe ring for phone case is another well-known ring magnet yet with multiple magnetism directions on a single magsafe ring. That depends on the purpose your would like to use with a permanent magnet. Tell me your request!