All three models use the same movement link that is common to the other 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 hours, minutes, and sub seconds, the 4400 AS ticks at 4 Hz, measures just link 2.8mm thick, and link carries the Hallmark of Geneva.