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 1.5 pounds. It has a stability temperature of 1,022℉, a hole diameter of 0.177 inches, and a tap size of 0.16 inches to 0.28 inches. It is made of Alnico five magnet material. It measures 1/2 length x 0.500 width x 0.375 height x 1/2 inches diameter.