R.E.A.D.Y. A Guide to Your Child's Development

This wheel is quite recent. It has a URL on it. This was produced by the Michigan State Board of Education. It's a guide to the expected childhood developmental milestones from one month to sixty months (otherwise known as 5 years, for Pete's sake). On the reverse is the recommended vaccination schedule, which is helpful.

This is, as you might expect, in excellent condition and measures 6.126 inches in diameter.