Cillian Murphy wears a Hamilton Cushion B

Christopher Nolan borrowed three vintage watches from Hamilton's archives to track 40 years of J. Robert Oppenheimer's life. The Cushion B is the earliest, an early 1930s model with Art Deco numerals and an ornate handset, worn by Cillian Murphy in the scenes set during Oppenheimer's time at Cambridge and Gottingen. Nolan insisted on genuine period timepieces rather than modern recreations, and Hamilton obliged by pulling pieces from their vault that had never been worn on screen.

The Cushion B gets its name from the cushion-shaped case, rounded corners on a square form, a design popular in the 1920s and 1930s when watchmakers were still experimenting with case geometry. Hamilton was an American company based in Lancaster, Pennsylvania, and in the early 1930s they were one of the few domestic manufacturers producing watches that could compete with Swiss imports on quality. Oppenheimer was a Berkeley physics professor who dressed well and cared about details. An American-made dress watch from this era fits the character and the period.