3.5" with metal back and bar pin. Reverse has .75" line where the celluloid is split with resulting very narrow gap along the edge of the metal back. However, this does not show from the front as a bump but rather only slightly in certain light angles as an air mark. Button also has a tiny raised bump as made caused by the reverse bar pin. Button still displays glossy and Mint. The best of only two we've offered in five decades. Issued for event at "Westwood Shrine Club Jan. 14th 1959." An extremely limited single day event button. Rare.