Perpetual Calendar
A calendar function that calculates and displays the date, day, month and leap year without any adjustment by the user. This remains true until the year 2100, when there is no leap year due to the Gregorian calendar. All watches record time, the moments that make up a day, but perpetual calendars keep track of all of those days. Depending on the watch, there are many different types of indicators that display the specific day, date and month.