AP 2240

The base measures 4.00 mm thick with a 21.30 mm diameter, operating at 28,800 vibrations per hour (4 Hz). It contains 28 jewels and offers a minimum power reserve of roughly 40 hours. The system features unidirectional automatic winding (clockwise from the dial side) via an oscillating weight on ceramic ball bearings, a 21-karat gold weight segment, a variable inertia balance, a flat hairspring, and a mobile stud-holder.