The Longines Avigation Watch Type A-7 was inspired by models developed during the 1930s that had to meet extremely stringent criteria from the point of view of appearance, quality and precision in order to be selected by aviators and bear the name "Type A-7" given by the U.S. Army. Their large diameter and fluted crown enabled them to be easily read and quickly manipulated, even if the pilot was wearing thick gloves. The angled black dial with its large white numerals also ensured easy reading in poor light or turbulence. The angle of the dial was specially designed for the chronograph to be worn on the inside of the wrist. This meant that the dial was aligned with the aircraft's instruments and the pilot could read the timepiece without moving his or her arm or letting go of the controls.