2.25" although the button has been flattened. In spite of the damage the front of the piece still displays NM and with just a tiny air spot over the few letters of the word "Engineering." The spring pin on the back can still be taken in and out but the channel it lays in was once deeper and has now been compressed. Button at top begins "IT Week/54th Annual." In addition to the school name and year further text reads "Progress Through Engineering/April 26-May 3." Fred is shown driving his car constructed from rock with small text on the hood and side "IT Week '68/Flintstone Special." Only example we've seen.