In the U.S. military, bars signifying the captain rank of military personnel are worn on the collar of the shirt. The captains wear two parallel silver bars, ¾-inch in width and 1 inch in length. Proper placement of the captain's bars is outlined in the Army's dress code, and is required for work, field and utility uniforms. Military dress code is strict, and as such, placement of uniform parts, like captain's bars, must be exact to meet dress code requirements.
Pin bars on the shirt collar vertically, one set of bars on each side.
Space bars ¼ inch apart.
Situate the bars so they are parallel to the shoulder loop's seam.