To celebrate ten years since the original Heart Beat Manufacture collection was launched, Frederique Constant has created two limited-edition Heart Beat timepieces: one in rose gold and the other in stainless steel. The signature feature of the watch is, of course, the large “Heart Beat” aperture on the dial that exposes the balance wheel and escapement as it beats back and forth at 4Hz (or 28,800 times per hour).

Notably, the new Heart Beat Cal. FC-945 has an advanced silicium escapement that uses less power and maintains amplitude more efficiently than a standard lever escapement because it functions without lubrication. The self-winding manufacture movement has 126 total components and a 42-hour power reserve. It features a Côte de Genève and perlage decoration. The oscillating weight has is gold-plated (even for the steel model) and has a Côte de Genève finish.

The Heart Beat timepiece is presented in a fully polished 42 mm diameter case with a fixed bezel and a ridged onion-style non-locking crown. The dial is protected by a convex sapphire crystal, while the caseback has a flat crystal. The dial is silver with a guilloché pattern and printed Roman numerals marking the hours. Functions include hours, minutes, date, moonphase (at 12 o’clock), and 24-hour second-time zone display (at 9 o’clock). The hour and minute hands are in blued steel and have a Breguet-style open-tipped design.

The Heart Beat Manufacture Calibre FC-945 Silicium will be available in limited editions of 188 pieces in 18K rose gold and 1888 pieces in polished stainless steel. They come on a brown or black alligator strap, with a matching pin buckle. The price is $6,500 in steel and $15,500 in rose gold.