18k gilt lever movement (Cal. 558) 21 jewels one-minute tourbillon carriage with mono-metallic compensation balance visible beneath the dial adjusted to 6 positions engine-turned silvered dial eccentric dial with Roman numerals blued steel Breguet hands semi-circular arc calibrated for 20 second intervals polished case milled band the back plate finely engraved with scroll motif sapphire crystal back case dial and movement signed.