What is the collar device for a LCDR in the Navy?

The collar device for a Lieutenant Commander (LCDR) in the Navy is a gold oak leaf. This insignia distinguishes the rank of Lieutenant Commander and is consistent with the Navy's ranking system, where ranks are represented by various symbols. The gold oak leaf specifically indicates a rank that is above that of a Commander (who wears a silver oak leaf) but below that of a Captain.

The use of the gold oak leaf as the collar device signifies the leadership and responsibilities associated with the rank, as well as the officer's experience and authority within the naval hierarchy. This form of insignia allows for easy recognition of the rank by other personnel, ensuring clear communication regarding the chain of command.