A perpetual calendar is one that can be used over and over for several years, in this case, and infinite number of years. The two knobs in front turn to change the month and the days, displaying one full week at a time.
This calendar is English, c. 1860-1880. It has a dramatic black lacquer finish with gold and mother of pearl inlay. It is functions perfectly, and is in excellent condition.
Dimensions: 8" x 5.75"