The M2 light tank led to the US M3-series and M5-series light tanks.
The Ordnance Department viewed the M2A4 as a stopgap tank; work to improve it further began in June 1940.
The first M3 Stuart tanks began to be produced in March 1941; the original riveted M3s closely resembled the  M2A4, and the two types occasionally served in the same units; an easy recognition feature was the rear idler wheel.
On the M2A4, the idler was raised; on the M3 it trailed on the ground, increasing the flotation of the heavier vehicle.
The M3 retained the same Continental W-670 engine, but incorporated ½-inch thicker (1½ inch total thickness) armor; with weight increased to 14 tons.
The tank initially kept the same 37 mm gun and the forward firing hull machine guns, but the turret incorporated improvements.
Eventually over 4,500 examples of all variants were produced.
The M2 light tank led to the US M3-series and M5-series light tanks. The Ordnance Department viewed the M2A4 as a stopgap tank; work to improve it further began in June 1940. The first M3 Stuart tanks began to be produced in March 1941; the original riveted M3s closely resembled the  M2A4, and the two types occasionally served in the same units; an easy recognition feature was the rear idler wheel. On the M2A4, the idler was raised; on the M3 it trailed on the ground, increasing the flotation of the heavier vehicle. The M3 retained the same Continental W-670 engine, but incorporated ½-inch thicker (1½ inch total thickness) armor; with weight increased to 14 tons. The tank initially kept the same 37 mm gun and the forward firing hull machine guns, but the turret incorporated improvements. Eventually over 4,500 examples of all variants were produced.
M2 light tank