This is a round countersunk hole magnet with an outer diameter of 20mm, height of 6mm, M6 holes, rare earth neodymium material, this type of magnet is more common, the surface is zinc plated, N50 grade, the surface magnetic field strength is higher than 4500 gauss, suitable for a variety of scenes that require a strong magnetic tape mounting and fixing, can be customized for other sizes, performance.
Some customers need paired magnetization, 2 together, please check if you need it.
More types of magnets with countersunk holes: https://www.couragemagnet.com/magnets-with-screw-holes/
You may want to know;
Why are countersunk hole magnets mostly rare earth neodymium?