1.75” picturing the famous comedy duo with text at top “Lou ‘I’m A Bad Boy’ Costello For Mayor Of World’s Fair Midway” while below photos of the pair is text “Abbott For Commissioner Of Laffs.” This example is without a back paper as is typical although we’ve seen one or two with a back paper from the exhibit “Streets Of Paris.” Those had a serial number meant to be matched to a number posted outside the exhibit at Michael Todd’s Hall of Music each evening to gain a free admission. These papers must have been inserted for certain days only and Bud & Lou must have been associated with the exhibit on a continuing basis as we’ve seen a flyer from the exhibit promoting this button with the phrase “Button, Button-Who’s Got The Lucky Button?” The flyer also indicated Bud & Lou made appearances at the “Streets Of Paris” to distribute their “Campaign Buttons.” There are numerous crude modern fakes of this button. This is the original distributed at the fair in 1939. NM displaying Mint.