Tudor Black Bay One 31

Tudor's Black Bay One 31, reference M79600-0002, is a steel watch measuring 31mm across. The case runs 9.5mm thick, with a 17mm lug width for the bracelet. A flat sapphire crystal covers the blue dial, its hands and indices treated with luminous material for visibility in low light. The self-winding calibre MT5201 drives the watch, certified as a chronometer and built with a bidirectional rotor system. Central seconds register from the same movement, which holds around 50 hours of power reserve. A screw-down crown, stamped with the Tudor rose, protects the movement. The steel bracelet closes with a folding clasp and safety catch. That clasp secures a case good to 100 metres.