This man-portable incendiary weapon is usually called a "man-pack" flamethrower. The backpack element consists of two or three cylinders. Some Russian flamethrowers have three fuel tanks. One cylinder holds flammable liquid and the other compressed propellant gas, usually nitrogen. A three cylinder system has two outer cylinders of liquid and a central cylinder of gas to improve the balance. The gas is used to force the liquid out of the cylinder into a pipe and then the gun part of the system. The gun attachment consists of a small reservoir, a spring valve and an ignition system; depressing a trigger opens the valve and allows the pressurized liquid to pass over the igniter and out of the weapon. The igniter can be one of a number of systems, a simple type is a wire coil which is heated electrically. A more complex, more reliable system has a small pilot flame fuelled by pressurized gas from the system.

It is a weapon with a potent impact on unprepared troops, delivering a particularly horrendous death; it can have great psychological impact. It is primarily deployed against battlefield fortifications. A flamethrower projects liquid rather than flame so the flaming liquid jet can be 'bounced' off walls or ceilings to project the fire into unseen spaces such as the interior of bunkers or pillboxes. Or, an unignited stream can be fired and afterwards ignited.

Flamethrowers also pose many risks for those using them. Their first disadvantage is that they are heavy and slow down a soldier's mobility. And although they are powerful, the actual time of constant flame firing is usually not more than a few seconds. Flamethrowers are also very visible on the battlefield, and become prominent targets for snipers or artillery such as mortars. Finally, and perhaps most obviously, flamethrowers have a very short range, meaning that soldiers wielding these weapons have to get very close to enemy positions to use them and thus are put at great risk. It is, however, unlikely that these weapons will explode when penetrated by enemy fire (much like shooting a can of petrol will not usually result in explosion), although penetration and subsequent fuel leak is an obvious explosion hazard as the fuel can be ignited by the pilot light or external sources.