The original Model 1A1 flamethrower was troubled by ignition problems which were corrected in the M2 version. The simple mechanics of the flamethrower are overshadowed by its destructive nature. Two tanks are mounted side by side in a backpack-type configuration. One tank contains fuel, usually a thickened gasoline. The other contains compressed gas. They are mixed as they pass through a valve. The gas provides the force to propel the gasoline. At this point, the mixture is ignited and a sheet of flame produced.