By law, a star is added to the U.S. flag on the 4th of July following the admission of a state to the union. This flag represents the addition of the state of Missouri.
It is important to note that no American flag ever becomes obsolete. This flag is still a legal flag and may be flown at any time. Made from fade resistant, outdoor nylon material, this historic flag includes appliqued stars and sewn stripes, white heading and grommets.