While chain-link closures are a feature of formal dress uniforms in all five branches of the Armed Forces of the United States, only the Marine Corps limits their use to the jackets worn by Staff Noncommissioned Officers, an NCO classification unique to the Corps. The other four services classify NCOs in the E-7 to E-9 grades as Senior NCOs; in the Marine Corps, “Senior” is swapped for “Staff,” and the range is expanded to include E-6 NCOs.
Per regulations, this chain-link closure features 27-line gold buttons embossed with the United States Marine Corps’ “Eagle and Anchor” design, which was first used on Marine Corps buttons in 1804. Buttons should be cleaned with a weak solution of ammonia and water; if they’ve turned green because the plating has come off and they’ve been exposed to moisture, try rubbing them gently with acetic (vinegar may be used) before washing them in fresh water and drying.