All three models use the same movement that is common to the other
link entries in the American 1921 family, Vacheron Constantin's hand-wound calibre 4400 AS. Seen through a wide display caseback, with 65 hours of power reserve supporting
link hours, minutes, and sub seconds, the 4400 AS ticks
link at 4 Hz, measures just 2.8mm thick, and carries the Hallmark of Geneva.