Vintage wooden perpetual calendar display date by rotating its concentric wheels How It Works Three Rotating Elements: It features separate rings or sections for the day of the week, the day of the month (1–31), and the month of the year.The Pointer: The small brass pin or pointer at the very top serves as the indicator line.Setting the Date: You manually turn each wheel until the current weekday, numerical date, and month line up vertically directly beneath that top pointer. Dimensions: 16x9