The Bulova 12B watch movement was an American-made, open face calibre movement produced between 1923 and 1928. It featured a stem wind and set function, as well as a sub second display. The movement incorporated sunk gold settings, a negative stem mechanism, a bimetallic screw balance with four adjustment screws, and a Breguet hairspring. A total of 33,800 units of the Bulova 12B movement were manufactured during its production period.