I have a perpetual calendar from between the 1940's - 1960's.  It is on top of a large paper clip. There are dials on both the sides to adjust the month, day and date.  It measures about 3 5/8" in L x 1 3/4" in W x 5/8" in H at the clip end, 1 1/8" at the center of the clip where the calendar is the tallest and 1/2" at the bottom edge where the clip opens.  The bottom is the same metal as you see on the top of the clip (it is a bit scratched).  The paper for the months, days and dates is slightly discolored.    I would consider this in fair condition.

Perpetual Calendar with Clip Great Vintage Office Piece