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. The TUDOR Black Bay Chrono S&G with a black, domed dial with a date function at 6 o'clock, a fixed yellow gold bezel with matt black anodised aluminium disc with tachymetric scale, yellow gold markings. The 41mm steel case houses a chronograph calibre MT5813 self-winding mechanical movement with a domed sapphire crystal that boasts a 70-hour power reserve. This handsome watch is set on a steel and yellow gold bracelet with a folding clasp and safety catch, is waterproof to 200m (660ft) and comes with a 5-year guarantee.