the field-grade equivalents. For midshipman ranks, both junior and senior officer equivalents wear from one to six 1/4" gold stripes or bars. US Air Force cadets wear rank shoulder boards or lapel insignia which carry miniature insignia identical to those worn by officer trainees at USAF Officer Training School. Service academies Each U.S. service academy has its own set of insignia, different from their corresponding ROTC program. U.S. Military Academy (West Point) United States Military Academy "class insignia" are worn on the collar and epaulets of certain uniforms. An enameled shield bearing a Greek sword surmounted by the helmet of Pallas, worn on the left collar or above cadet rank stripes/bars on epaulets, is the standard class insignia for third-class (yellow shield), second-class (grey shield), or first-class (black shield) cadets. On traditional "dress grey" and "full dress grey" uniforms and overcoats, the class insignia is indicated by the number of service stripes (one to three) denoting completed years at the academy. These stripes are located on the lower sleeve for the under two classes and on the upper sleeve for the upper two classes. Visitors are sometimes confused to see cadets early in the academic year wearing the insignia of cadet private first class - such cadets are often reduced in rank (for any of a variety of reasons), but have already completed their first year and as such are no longer cadet privates ("plebes"). Rank within the Corps of Cadets is denoted by collar insignia "railroad tracks", a number of black enamel bars with silver outline, or epaulet stripes from one (for cadet corporal) to six (for cadet captain in certain command and staff roles) on certain uniforms. On the traditional dress-grey-based uniforms and overcoats, chevrons denote rank in the Corps. A cadet corporal wears two chevrons on the lower sleeve. A cadet sergeant wears two chevrons on the upper sleeve, a cadet lieutenant three, and a cadet captain from four to six chevrons. For cadets in the rank of cadet sergeant and up, various combinations of stars, diamonds, rockers or arcs, and other devices, are used on the sleeves to denote specific positions/jobs. The title of cadet captain is used for all cadets wearing four or more stripes/bars. The brigade commander, also called the first captain, wears six stripes/bars/sleeve chevrons with a gold star U.S. Air Force Academy The rank of United States Air Force Academy cadets is