Bulgari BVL-100

The BVL-100 is a manual-winding in-house caliber introduced by Bulgari in 2022. Measuring just 5.4mm in diameter, it is among the smallest mechanical movements produced. Unlike traditional designs, it has no external crown—winding is performed through a key-wound system integrated into the caseback, transmitting power to the mainspring via ratchet wheels. The movement powers Bulgari's Serpenti Misteriosi secret watches.