Which device signifies an O-6 in the Navy?

In the Navy, the rank of O-6 is held by a Captain. The insignia that signifies this rank is a silver spread eagle. This eagle represents authority and command and is placed on the officer's shoulder boards or uniforms to indicate their rank. The spread eagle design is significant in military insignia as it symbolizes freedom and strength, aligning with the responsibilities of an officer of such a rank.

In contrast, one gold oak leaf represents the rank of Lieutenant Commander (O-4), while one silver bar denotes a Major in the Marine Corps or an O-3 rank in the Air Force, and two attached silver bars indicate the rank of Colonel (O-6) in the Army or Air Force, not the Navy. Each branch of the military has its unique insignia system, and understanding these symbols is crucial for recognizing ranks and the hierarchy within the Navy.