Function: to achieve the 1/12 ratio between the minute-hand and the hour-hand of the flyback.

 
Base plate: decorated (satin-brushed and black gold) and pre-mounted (assembly of the jewels, wheels and pins)

The center wheel holds the hour hands. It makes one rotation every 12 hours.

This bridge has been treated in black gold.

This bridge has been treated in black gold.

Bridge of Differential treated in black gold.

Bridge of Trust index treated in black gold.

Bridge of module: hold the elements of the power reserve indicator, hour and minute together.