The first Longines Lindbergh Hour Angle Watch is from 1931 and has a diameter of 47.5 millimeters. Which is a perfect size for navigation or pilot watches. It has the Longines 18.69 N.S.C. caliber, a hand-wound mechanical movement housed in a sterling silver case. This caliber is originally a pocket watch movement, like most navigation watches at that time. The dial is white with champagne. Around 2,000 pieces where produced, made by Longines and distributed in the US by Longines-Wittnauer.
Herein is an explanation - of sorts - of how the watch works. The Hour Angle hand shows an equivalent to longitude but not in degrees but in an angular distance representing the time difference between Greenwich (GMT) and any other point on the Earth. So, somehow, if you can measure your position, with a sextant, to a certain celestial element, and you can look up where that element would be on a certain time at Greenwich and you know your own time you can calculate your longitude and latitude. More or less. To be honest, it is the closest way for us to describe how it works, but by far not accurate. For example, there is phenomenon called Equation of Time, the difference between ‘the time on Earth and the time above us’. For that the rotating bezel contains a sort of correction scale.