50 years Perpetual Calendar

How to use:

◉ Turn the upper disc, aligning the year and month you are to seek, then the diagonal direction will show you the week information of each day in the month

◉ You can know the week of every day in the range of 2007-2056

◉ When you seek for January or February in a leap year, you should aligning with the orange "JAN" and "FEB"

For more, please visit: https://en.wikipedia.org/wiki/Perpetual_calendar