It's the ball gun turret from a WWII B29 Bomber. These hung below the bellies of the bombers and allowed the gunner to spin 360 degrees as well as pivot up and down. The two smaller holes are for the .30 caliber machine guns to fit through. See here: http://www.dark-history.eu/ball_turrets.htm
Men's XL Ash Grey please. :)
Sent from my eyephone - it's the future!