Pilot #3 was constructed in November 1952 and used the Mod B hull and turret designs with a simplified, larger diametered hatch that was easier for the driver to operate. Also the front vision block was removable and allowed for the future use of IR vision blocks by the driver. It also had 5 return rollers, 6 roadwheel pairs per side with the drive sprocket at the rear and a torsion bar suspension system. The Mod B turret also had larger hatches for the commander and loader. An additional three hulls were constructed (T48 pilots 4 through 6) in 1953. These tanks were used into 1955 for the component development of the M48A2 production tanks including fire control systems, turret cupolas, suspension configurations and powerpacks. At least one of these hulls was fitted with experimental silicas glass composite armor panels.