Cal. 557 nickel-finished lever movement fully hand-engraved with scrolls movement plate signed Tourbillon Breguet No. 2009 Brevet du 7 Messidor An 9 21 jewels one-minute tourbillon carriage with mono-metallic compensation balance visible beneath the dial at six oclock silvered striped dial with off-centered hour dial with Roman numerals all concealed under a hinged engine-turned cover with porthole and plaque engraved Tourbillon the enterior of the cover lid hand engraved with the signature of Nicolas G. Hayek opened by pressing a button in the crown the large circular case with coin-edged band sapphire crystal display back case dial and movement signed with a platinum Breguet deployant clasp