Antique wall clock

Mechanical structure: The dial has two mainspring holes (commonly known as "double springs" or "two eyes"), making it a typical 15-day mechanical clock. The left hole is responsible for striking the hour, while the right hole is responsible for maintaining the power source for timekeeping.

These old-fashioned Polaris mechanical clocks are very robust; once wound up, they can still produce a clear "tick-tock" sound and chime on the half-hour and hour.

The "thump-thump" sound of striking a steel ring or spring to indicate the time.