In the 2000s, the Swiss watch industry turned to silicon components for their superior reliability, durability, resistance to magnetism, and light weight. But Richemont was left out of these developments, so it wasn't until 2017 that the group introduced their first production silicon watch component, the "Twinspir" hairspring first found in Cal. BM12-1975M. This hand-winding movement was developed and produced by ValFleurier, the movement specialist within Richemont, and first appeared in the limited-production Baume & Mercier Clifton Manual 1830.
The following year, Baume & Mercier introduced Cal. BM12-1975A, an automatic version with the Twinspir hairspring and the new "PowerScape" silicon escape wheel and anchor, another first for Richemont. The combination of these technologies and an optimized wheel train and barrel deliver an impressive 5-day power reserve, along with magnetic resistance and COSC chronometer certification. This movement was fitted to the inexpensive, full-production Baume & Mercier Clifton Baumatic.
All versions of Cal. BM12 feature a free-sprung balance with four adjustable masses on the rim. The basic structure resembles the ETA 2824 but differs in many technical respects and is not based on that ebauche.