What distinguishes the shoulder device of an O-6 in the Navy?

The shoulder device of an O-6 in the Navy is distinguished by four half-inch gold stripes. This pattern is standardized for the rank of Captain in the Navy and reflects the seniority and authority associated with this rank. The four gold stripes symbolize the progression and experience that an officer has achieved, differentiating them from lower ranks, which feature fewer stripes. Each stripe represents a step in rank, with each half-inch gold stripe denoting a specific level of authority and responsibility within the naval hierarchy.

This distinction is important for identification purposes within the military structure, as it allows for quick recognition of an officer's rank by both peers and subordinates. In contrast, other options reflect either incorrect stripe counts or symbols that do not apply to the rank of O-6 in the Navy.