In the United States military, a general is the most senior general-grade officer; it is the highest achievable commissioned officer rank (or echelon) that may be attained in the United States Armed Forces, with exception of the Navy and Coast Guard, which have the equivalent rank of admiral instead. The official and formal insignia of "general" is defined by its four stars (commonly silver and in a row). Since the ranks of General of the Army and General of the Air Force are reserved for wartime use only, the rank of general is the highest general officer rank in peacetime.