Mechanical Hi-Beat 36000 80 Hours, Caliber 9SA5
For the fine tuning of the escapement’s precision, a new free-sprung system which does not have a regulator has been incorporated. The four screws on the side of the balance can be turned to adjust the moment of inertia of the balance, allowing for fine tuning to make the watch faster or slower. As there is no regulator, the durability of the hairspring is increased, as is the precision over time.
The Grand Seiko Free-sprung Balance is equipped with a mechanism that alters isochronism under fixed conditions when the stud at the end of the hairspring rotates. Thus, it is possible to adjust the isochronism while still remaining a free-sprung system with no regulator.