While a Perpetual Calendar technically refers to a calendar system that can be used for any year, it is commonly used to describe a date display mechanism often found in mechanical watches.
A Perpetual Calendar, in essence, can be considered as a calendar that continues endlessly. By using mechanical components to adjust the “year” and “month” each time the month changes, the dates for the month are displayed on the calendar.
“Perpetual Calendar Opener, Keychain”
You can find a product on AliExpress that serves as both a keychain and a bottle opener. It is a small item, and nowadays, with the convenience of checking the calendar on our phones, its practicality may be limited.
However, the product carries a unique atmosphere, reminiscent of the mysterious feeling conveyed by a “Perpetual Calendar.” With the added function of being a bottle opener, it becomes an interesting item to use when you need a bottle opener.
- AliExpress “Perpetual Calendar Opener”: https://s.click.aliexpress.com/e/_A426Bo