Swiss antique unsigned double-sided chronograph pocket watch 800 silver case in good working condition

We would like to acknowledge an unbranded Swiss made pocket watch.

This is an unbranded clock from an unknown maker, thought to be from around 1900.
This is a very rare pocket watch with a dial on both sides, one side being a regular clock and the other side being a stopwatch (chronograph).
The case is made of 800 silver, is quite thick and has a heavy feel.
It is unknown whether it has been overhauled, but the balance wheel is in good condition and ticks along smoothly.

We hope this once-in-a-lifetime encounter will be a special one for you!

(Explanatory video)
https://youtu.be/CG-3PvPWmk4?si=yLE8mFtiWTC7Qw7e

【condition】
Appearance: ★★★☆☆ Slightly damaged and dirty

Function: ★★★★☆ Maintenance history unknown but in good working condition (daily accuracy within 5 minutes)

- Case: Has signs of wear and tear, small scratches and dents, but is well maintained
-Case engraving: Swiss 800 silver engraved on the bezel on the chronograph side
-Dial: There are cracks and chips on both sides, but they do not affect visibility.
Other: The crown is quite stiff when winding the mainspring.
Accuracy: Approximately 4 minutes per day when measured with a flat timegrapher
Power reserve: up to 29 hours from full spring

*The daily difference may vary depending on posture, so please use this as a reference only.
*Because it is an old item, I do not know the history of parts replacement or repairs.

【detail】
・Brand: Unknown
- Year of manufacture: Around 1900
Movement: Mechanical
・Mainspring: Manual winding
・Time setting, dowel pressing (nail set)
・Serial No. 74428 (case)
・Case material: Continental silver (800/1000)
・Case diameter 50mm (excluding crown)
・Case thickness 21mm (including windshield)
Weight: 100g

*This is a vintage item and there are no other items exactly like it.
※If you have any questions, please feel free to ask.