Why can I hear my automatic watch ticking?
An open balance wheel is a visible area of the mechanical movement, where the balance wheel can be seen on the dial or through an opening.
The balance wheel is a central component of a mechanical movement. It swings back and forth evenly and helps regulate the pace of the watch.
In models with an open balance wheel, this movement is deliberately made visible.
The open balance wheel is mainly a mechanical design element. It doesn't fundamentally change how the watch is used, but it does make the work of the movement visible.