Cal. 554 nickel-finished lever movement engraved Brevet du 7 Messidor An 9 25 jewels the engine-turned white dial with Roman numerals on blank silvered chapter ring blued steel Breguet hands the three-armed one minute tourbillon carriage with monometallic balance exposed through a glazed aperture to 12 oclock combined with constant seconds two subsidiary dials indicating 30 minutes and 12 hours registers in circular case with coin-edged band glazed display snap on back two round chronograph buttons in the band 18K white gold Breguet deployant clasp case dial and movement signed