Tanks in World War II bulldozer blade), the T34 Calliope (mounting a multiple rocket launcher above the turret), the M4A3R3 Flame thrower (flame tank), and the Sherman Crab Mark I (a M4 Medium with a mine flail), as well as many other variants. The United States eventually deployed the Light Tank M24, an improvement over the M3 Light Tank. The M24 had torsion-bar suspension, high mobility, and a compact 75 mm gun. Ergonomically the tank was quite good also. However, the M24 did not appear in combat until December 1944 and equipped only a few units by the end of the war. Near the end
Opposition to the war in Afghanistan (2001–2014) entering an eleventh year on October 7, 2011 and marking for the U.S. the longest period of sustained warfare in its history – greater than the time the United States was involved in World War I, World War II and the Korean War combined.<ref name="War and Sacrifice in the Post-9/11 Era"></ref> The war in Afghanistan surpassed the length of official U.S. participation in the Vietnam War, 8 years and 5 months, in the spring of 2010 to become the longest-running U.S. war ever. According to a study by the RAND Corporation, an American think tank working for the U.S. military,