Tudor watches, particularly the Submariner model (ref. 7928 and others), were frequently used by Navy SEALs and other Special Operations Forces (SOF) during the Vietnam War, often mistaken for Rolex watches. These watches were issued to SEALs and sometimes purchased from PX stores, and featured "CASE BY ROLEX GENEVA ORIGINAL OYSTER" on the caseback and the Rolex crown on the crown. They were used for timing operations and dives, and sometimes modified with leather covers to minimize light reflection