What grade is the perpetual calendar watch?

This product belongs to high-grade watches.

The perpetual calendar watch is not only an ornament, but also a complicated functional watch. It has the function of automatically displaying month, date and week, and can identify the date of each month and leap year, and can adapt to different times and regions.

Perpetual calendar watches usually use top-class homemade brand movements, and the materials are mostly precious metals, such as ruby and platinum, which have higher accuracy and the error is within 10 second. It belongs to high-end products.