The Singapore Armed Forces (SAF) has two rank structures. One rank is structured similar to other military hierarchies in other countries. One major difference is that the SAF uses a unified rank structure, with identical rank names and insignia throughout the Army, Navy, and Air Force. For example, traditional navy ranks such as ensign and commander have been replaced with army-style ranks. Only two exceptions exist to the unified rank structure. Firstly, among the flag officer ranks, the navy retains the admiral ranks. The second exception is for the rank insignia for private and private first class in the Air Force, Army and Navy.