Based on Frederique Constant's first in-house manufacture automatic movement, the FC-930 "Heart Beat Manufacture", the FC-985 is closely related to the FC-980 tourbillon. It runs at 28,800 A/h, has 33 jewels, and a power reserve of 48 hours. It is finely decorated with guilloché and Côtes de Genève. The dial includes central hour and minute hands, small seconds on the tourbillon, a date and moon phase subdial at 12:00, and a day/night painted 24-hours indicator at 9:00. Inside is a silicon escapement wheel and lever.