My friend Nancy brought this back from Guatemala. It's pretty fancy, I think. The Mayans had more than one calendar. There was your usual solar calendar and a ritual calendar. The 260-day ritual calendar is called Cholq'ij y el Ab' and that is the calendar described on this wheel.
There is a little booklet tucked inside with pages and pages and pages of E-Z instructions. Mayan symbols are very interesting and beautiful. I like the ones on the middle wheel (which has the names of the days). They look like little televisions!
This wheel is, pretty much, brand new and shiny. The disk measures 7.375 inches.