Twinspir is a dual-layer silicon balance spring material used by Richemont's ValFleurier since 2017
Richemont was a decade behind the Swiss watch industry in developing a silicon balance spring, not being part of the Rolex/Patek Philippe/Swatch Group/CSEM group that developed and patented such materials. Twinsipr is a very different material as well It features two layers of silicon material bonded together with their crystal structure oriented in opposite directions. A third layer of silicon dioxide is used to bond the two layers together and provide temperature compensation.
Twinspir was introduced to the market in the limited-production 2017 Baume & Mercier Clifton Manual 1830 before being introduced to full-production in the 2018 Baume & Mercier Clifton Baumatic. In 2019 it was revealed that CSEM had threatened legal action to prevent further use of Twinspir and the product was rapidly withdrawn from the market.