By October 1954, the Army decided to amend the design of the tank by installing a cupola. During the production of M48s it was modified several times resulting in a wide mix of cupola styles among individual tanks. Afterwards it was renamed as the Cupola, Tank Commander's Caliber .50 Machine Gun, M1. The new tank commander cupola would allow the tank commander to aim and fire his weapon while remaining under armor protection via a remote controlled M2HB machine gun, however the commander had to open the cupola hatch and expose his head to reload or service the machine gun due to the limited headroom. These cupolas had a small rearward opening hatch and a single, non-removable vision block. They were designed by Aircraft Armaments Incorporated. Because of its smaller turret roof hatch opening those M1 cupolas retro-fitted to early production M48 Mod A turrets used an adaptor ring.