The rest so far are assumed from knowledge of the Metonic cycle.
This fragment also contains a single gear (o1) used in the Olympic train.
Clearly visible on the front is the large b1 gear, and under closer inspection further gears behind said gear (parts of the l, m, c, and d trains are clearly visible as gears to the naked eye).
The crank mechanism socket and the side-mounted gear that meshes with b1 is on Fragment A.
Contains approximately the bottom right third of the Metonic spiral and inscriptions of both the spiral and back door of the mechanism.
The Metonic scale would have consisted of 235 cells of which 49 have been deciphered from fragment B either in whole or partially.
He initially believed that it was an astronomical clock, but most scholars considered the device to be prochronistic, too complex to have been constructed during the same period as the other pieces that had been discovered.
It is a complex clockwork mechanism composed of at least 30 meshing bronze gears.
Other fragments may still be in storage, undiscovered since their initial recovery; Fragment F came to light in that way in 2005.
Of the 82 known fragments, seven are mechanically significant and contain the majority of the mechanism and inscriptions.
The mechanism's advanced state of corrosion has made it impossible to perform an accurate compositional analysis, but it is believed that the device was made of a low-tin bronze alloy (of approximately 95% copper, 5% tin).
In 2008, continued research by the Antikythera Mechanism Research Project suggested that the concept for the mechanism may have originated in the colonies of Corinth, since they identified the calendar on the Metonic Spiral as coming from Corinth or one of its colonies in Northwest Greece or Sicily.