The M2A4 Light Tank was the main production version of the series. Was developed at the Rock Island Arsenal.
Standardized in 1939. 37 mm gun mounted in the single turret. Hand traverse. Fired an 1.9 lb AP shell at a velocity of 2,900'/sec. The .30 cal MG filed a shell at 2,800'/sec. Few late production vehicles had Guiberson T1020 diesel.