The M551 Sheridan is a light tank developed by the United States during the 1960s. It features a unique aluminum hull and is equipped with a 152mm gun that can fire both conventional rounds and the Shillelagh missile. Designed for air mobility, the Sheridan could be transported by helicopters and was intended for rapid deployment in various combat scenarios. The M551 Sheridan saw service during the Vietnam War and was used by U.S. forces until the late 1990s. Its lightweight design allowed for greater maneuverability, but it faced criticism for its armor protection and firepower compared to heavier tanks. Despite its limitations, the Sheridan played a significant role in U.S. armored warfare history.