The Black Bay GMT is an extension of the Black Bay line with a highly functional complication: a multiple time-zone function – also known as a GMT function. Enhancing the Black Bay with yellow gold creates a version named S&G, for Steel & Gold. TUDOR derived the characteristic aesthetic elements of the Black Bay S&G model from its history. The overall shape, as well as the domed dial and crystal, come from the first TUDOR divers’ watches. In this version the lines and proportions of the Black Bay are retained, while the rotating bezel and the winding crown are made from yellow gold.