This button magnet is made of Alnico five magnet material. It is a cylindrical magnet with poles in one plane and has a maximum pull of 7.5 pounds. It has a stability temperature of 1,022℉, a hole diameter of 0.188 inches, and a tap size of 0.22 inches to 0.34 inches. It is made of Alnico five magnet material. It measures 1 length x 1 width x 5/8 height x 1 inches diameter.