The Sirius Retrograde Day ref. 8121 comes in a solid 29-part red gold case topped with a screw-down polished bezel with full thread, and it is completed on both sides by an anti-reflective sapphire crystal. The 40mm case also bears an onion-style crown in red gold and screw-in lugs with patented Autobloc System; it is water-resistant to 3 atm.
On the two dials available - either dark grey or terracotta - run gold-plated hands, hand-finished, and Feuille-shaped.
The watch is powered by the Chronoswiss Caliber C.286, beating at the frequency of 28.800 vph, and including a three-legged Glucydur balance and a Nivarox I balance spring. It offers a power reserve of 42 hours and displays sweep hours, minutes and seconds, a date window at 12 o´clock, and the retrograde display of the day. The special features include a skeletonized rotor with côtes de Genève, ball bearings, a polished pallet lever, escape wheel and screws, and plates and bridges with perlage.
A Louisiana crocodile leather strap, equipped with a pin buckle or folding clasp, completes the timepiece.