The fragment is approximately 30 mm thick at its thickest point.
Fragment A also contains divisions of the upper left quarter of the Saros spiral and 14 inscriptions from said spiral.
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.
The device was found housed in the remains of a 340-millimetre (13 in) × 180-millimetre (7.1 in) × 90-millimetre (3.5 in) wooden box.
It is a complex clockwork mechanism composed of at least 30 meshing bronze gears.
This motion was studied in the 2nd century BC by astronomer Hipparchus of Rhodes, and it is speculated that he may have been consulted in the machine's construction.
Its remains were found as one lump, later separated into three main fragments which are now divided into 82 separate fragments after conservation works.