In World War II, flamethrowers were used often. Flamethrowers can disable protected emplacements such as bunkers. Flamethrowers were first introduced in the trench warfare of World War I. In 1939, the armed forces of Germany deployed man-portable flamethrowers, and the allies deployed their's in 1942. The main flamethrower for Germany was the Flammenwerfer 35, a man-portable flamethrower. It weighed 35.8 kilograms, and had an effective range of 25 meters. It also held 11.8 liters of fuel for it. There was also a later, upgraded version named the Flammenwerfer 41. The main flamethrower for the United States was the M2 Flamethrower, It had an effect range of 20 meters, weighed 30.8 KG, and held 4 gallons of fuel for the weapon. Infantry portable flamethrowers soon fell out of use as flamethrower tanks negated the risk of putting an infantry man in harm's way with a flamethrower, the tanks provided much more safety.