This rare button commemorates the last and longest of the Mercury flights which launched May 15, 1963. Cooper was the first American to sleep while in orbit and the last to launch alone on a solo mission. Button has tiny black dot as printed on rim edge at 10 o’clock. The covered metal back is a bit wobbly but does not come loose and this is as it was made. We believe the only example we’ve seen of this. Rare.