These are actual arming switches from the Little Boy 15 kt atomic bomb which the Boeing B-29 Superfortress Enola Gay dropped on the Japanese city of Hiroshima on the 6th August 1945. Three green ‘safe’ plugs were kept in the bomb during take-off and during the flight to the primary target. On the approach to the target the green plugs were removed and replaced with red ones. The bomb was now armed. The green plug is one of the actual ones used. The red plug is a spare. The actual red plugs were destroyed when Little Boy exploded at an height of 1900 feet.
A pair of the plugs were sold at auction in 2002 for $167 000. The purchaser was Clay Perkins, a retired physicist in Rancho Santa Fe, California. The Enola Gay’s weaponeer Morris Jeppson had kept the plugs as souvenirs and they were sold with labels he wrote in 1945.