The 50-year pocket calender measures 3" x 1". 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. Locate the particular date and find the day of the week above it. It's heavy marble base with brass calendar disc make for a classic desk accessory or paperweight. Compass rose & mermaid designs flank the rotating dial.