In 1920, the Army rank and pay system received a major overhaul. All enlisted and non-commissioned ranks were reduced from 128 different insignias and several pay grades to only seven rank insignias and seven pay grades, which were numbered in seniority from seventh grade (lowest) to first grade (highest). The second grade had two rank titles: first sergeant, which was three stripes, two rockers, and a lozenge (diamond) in the middle; and technical sergeant, which was three stripes and two rockers. By World War II, the rank of first sergeant had been elevated to first grade and a third rocker was added, with the lozenge in the center to distinguish it from master sergeant. The wearing of specialist badges inset in rank insignia was abolished, and a generic system of chevrons and arcs replaced them.