This is an original  RARE Martin B-26 Marauder Bomber Martin 250CE Upper Turret Gunfire Interrupter. This item is built into the Martin 250 CE. upper turret used in the B-26, B-24, Lancaster bomber, A-20 Havoc and more. To keep from shooting their own aircraft with this turret they built in a gunfire interrupter. This device follows the chrome disk as it rotates and stops shooting when it get to a part of the aircraft that the guns might hit. This chrome plated disk is unique to the B-26. The exact same turret in another aircraft would have the chrome cylinder with its aircraft engraved into it.  It is 11 x 2 x 2 inches .   The B-26 Marauder is a medium range bomber. The bomber saw lots of action in both Europe and the South Pacific. Today there are no B-26 Marauders currently still flying. The Smithsonian Air & Space Museum is in the process of restoring the famous Flak Bait. That aircraft has more combat missions than any other  bomber.  This item is being sold as a collectable. Buyer to pay actual shipping.