The Tourbillon Bi-Cylindrique was introduced in 2011. Its hand-wound caliber MB M65.63 is housed in an oversized case with a bulge at 6:00 for the ‘mysterious’ hours and minutes. It is the world’s first wristwatch to feature a tourbillon with double cylindrical balance springs, which were originally developed in the 18th century for marine chronometers. Because the two cylindrical balance springs develop respiration in opposition to each other and maintain identical torque, the isochronism is even further optimized for extreme precision in the watch’s movement.
