For your consideration, here is a 1994 Rossmoor 30^th Anniversary Pinback Button, Pin, from Walnut Creek, California, 1964 - 1994.  It has a little wear on it.  The button has a diameter of 2 1/8 inches.  Item pictured is the actual item up for sale and comes from a non-smoking household.  (605.157j-.3px2)