Calibres Mb M29.21 And Mb M29.24 Exo Tourbillon Slim - Montblanc MB M13.21 Manual Del Usuario

44 45
Calibres MB M29.21 and MB M29.24 Calibres MB M29.21 and MB M29.24
Exo Tourbillon Slim
Available in the 4810, Bohème and Heritage Chronométrie Collections
The Manufacture Exo Tourbillon calibres MB M29.21 and MB M29.24 are automatic movements that
combine all the attributes of the art of top-quality watchmaking.
Their mechanism, of absolute accuracy, contains a tourbillon of patented design.
This calibre has a large balance-wheel oscillating at 21,600 vibrations per hour (3 Hz), located outside the
tourbillon cage. This innovative, patented mechanism is called the "Exo Tourbillon", from the Greek prefix
"exo", meaning "external" or "exterior".
The advantage of this construction is that it allows the use of a smaller, and therefore lighter, cage, needing
less energy to drive its rotating motion. The rotating cage is also relieved of the weight of the screwed balance:
this technical feat further reduces the energy required since the balance, isolated from the rotating cage, is not
disturbed by the cage's inertia.
In addition, the calibre features a stop-seconds function that stops the screwed balance-wheel directly, by
means of a small spring.
Such a device rarely accompanies a tourbillon and is very useful when the wearer wishes to make a precise
adjustment, not only of the hours and minutes hands, but of the seconds hand as well.
This calibre, which possesses a micro-rotor, is extremely slim (4.5 mm) and elegant with fan-motif Geneva
stripes.
Its power reserve is about 48 hours and it is remarkably comfortable to wear.