The M2-2 flamethrower was an American portable backpack incendiary device that was used in World War II. It was the successor to the M1 and M1A1 flamethrowers and offered improved reliability and a more efficient ignition system than previous models. It had a "burn time" of around seven seconds and the flame was effective out to around thirty-three meters. In 1944, the M2-2 flamethrower was introduced into service. It was first used in combat in Guam and was thereafter employed in all Pacific campaigns. Flamethrowers proved highly effective in fighting against the Japanese, especially in routing defenders from caves, pillboxes and underground emplacements. The arrival of flamethrowing tanks, which offered personnel protection and more firepower, lessened the Army's interest in and tactical use of portable flamethrowers. The M2 was upgraded for use during the Korean War (M2A1-2) and Vietnam War (M2A1-7), and eventually replaced by the lightweight M9A1-7. However, these were shelved after 1978 when the Department of Defense unilaterally stopped using flamethrowers on the grounds that they are inhumane and have little combat value. Created in 1944, this field manual reveals a great deal about the M2-2's design and capabilities. Intended as a training manual for those charged with operation and maintenance, it details many aspects of its controls, tools and accessories. Originally labeled restricted, this manual was declassified long ago and is here reprinted in book form. Care has been taken to preserve the integrity of the text."