The Breguet Marine Big Date (Reference 5817ST/12/5V8 or 5817ST/12/SM0) is one of the most celebrated modern luxury sports watches. It perfectly bridges Abraham-Louis Breguet’s historic appointment as the official chronometer maker to the French Royal Navy with contemporary sports-luxe design.

• Case Dimensions: 39mm diameter, 11.82mm thickness, and 50mm lug-to-lug. It wears slightly larger on the wrist due to the prominent lug design. 

• Dial: Solid gold dial base hand-engraved on a rose engine to produce a stunning wave/spiral guilloché pattern. It features individual applied, fired-blue steel Roman numerals and classic luminescent-tipped Breguet "pomme" hands.

• Complication: A distinct, independent double-disc "Big Date" aperture framed at the 6 o'clock position. 

• Case Architecture: Polished and brushed stainless steel with Breguet's signature fluted (coin-edge) case band, a screw-down crown with wave-motif guards, and 100 meters (10 ATM) of water resistance. 

• Movement: Powered by the in-house Caliber 517GG (based on the premium Frédéric Piguet 1150). It incorporates an antimagnetic silicon hairspring, twin barrels yielding a 65-hour power reserve, and a spectacular 18k gold winding rotor shaped like a nautilus shell.