For your consideration, here is a 1986 Portland Light Rail Grand Opening Pinback Button, Pin, for 5, 6, 7 September, Oregon.  It has some wear on it and a little tarnish on the back.  There is an old Goodwill pice sticker on the back of 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.  (441.806L-.4px2)