In the United States Army, the SEA for a battalion or larger-sized unit is usually a Command Sergeant Major. For Marine battalions and larger, Sergeant Major typically takes the role. Navy ships and other commands will usually have a Command, Fleet, or Force Master Chief Petty Officer (known as the Chief of the Boat on a submarine), while an Air Force Command Chief Master Sergeant serves at Wing, Numbered Air Force, Field Operating Agency (FOA), Major Command or at "Joint," DoD Agency levels.