In the 1880 most army units had buttons with a distinctive design. In 1821 officials decided to use a button showing an eagle over a shield with a simple letter I on the shield. Enlisted men used the design until 1854 when it was replaced by the general service button without the letter I. Infantry officers continued to use the old style during the Civil War. All buttons are non-dug Civil War era, and have the shank attached. They are of various backmarks.