For the new Ingenieur Constant-Force Tourbillon, IWC has integrated a patented constant-force mechanism into a tourbillon. It ensures that the amplitude of the balance – and thus the watch’s accuracy – remain absolutely constant, initially by disconnecting the escapement from the direct flow of energy generated by the gear train. The energy is stored temporarily in the balance spring from where it is transferred to the escape wheel. In the process, the balance spring is put under tension once a second and the seconds hand in the tourbillon advances in one-second jumps. This ensures an extremely regular and precise rate over a period of at least 48 hours. After approximately two days, the movement switches from constant-force mode to normal mode, as can be seen from the second hand, which now starts to advance at intervals of one-fifth of a second.