Authentic Models BC006 50-Yr Calendar Its origin goes back some 500 years An early, simple pocket calculator from an era when 50 years were akin to perpetual Intriguing, also effective Calculate the day of the week for any given future date, within a 50-year span To use, simply rotate dial until the selected year lines up with the selected month Calculate the day of the week for any given future date, within a 50-year span