This great button features the Niels Bohr model of a lithium atom. This model was developed by Niels Bohr and Ernest Rutherford in 1913 and was popularized for the general public after World War I. This button is white metal, with a two-piece construction and a metal self shank. The button measures 1/2" in diameter and is in excellent condition. These buttons would be great for a shirt for a physicist or science teacher. They would also be great for a collector's card on science or physics, or the cold war.