First Sergeant. First Sergeants can be in the pay grades of E-7, E-8, or E-9. The first sergeant exercises general supervision over all enlisted personnel assigned to the unit, even if they technically outrank the "shirt" via pay grade. That's because the first sergeant works directly for the unit commander and derives his/her authority directly from the commander. When the first sergeant acts or speaks in his/her official capacity, he/she is acting or speaking "for the commander," in all matters relating to assigned enlisted personnel. The first sergeant’s role is time honored and rich in custom and tradition. A distinguishing diamond device on the chevron identifies the first sergeant. As the vital link between the commander, enlisted personnel, and support agencies, the first sergeant must ensure the enlisted force understands the commander’s policies, goals, and objectives, and that support agencies are responsive to the needs of unit personnel. Additionally, the first sergeant must remain vigilant for and move to resolve issues that, left unchecked, would adversely impact troop readiness.