Rank insignia are worn as stripes on the cuff of both sleeves for officers above the rank of ensign. (Star Trek: The Original Series) As with a majority of Starfleet's uniforms, these insignia and the corresponding uniform designs were gradually introduced and worn over the years by Starfleet personnel in multiple realities. This includes the corresponding uniforms worn in the mirror universe by the Terran Starfleet. (See: alternate reality.)