Description - A specially designed Colt 37mm magazine for use in the prototype Vultee XP-54 aircraft. It has a capacity of 59 rounds and is designed to pass through the bulkhead of the plane for assembly within the aircraft. Magazine equipped with a Colt designed booster mechanism. Notes - Inscription on back: "Special 37 m/m magazine designed & built by Colt's/capacity 59 rounds/This magazine designed especially to pass through bulkheads of plane XP-54. Therefore, magazine made up in sections to facilitate assembly in plane. Plane mounted two 37 m/m guns firing through nose. Magazine equipped w/Colt designed booster mechanism."