The wrist-mounted flamer - also called a flamethrower gauntlet - was a miniature flame projector used during Great Galactic War and beyond. A corded fuel line connected to a backpack canister which held enough fuel for several minutes of operation.
The flame projector shot a jet of ignited liquid that had a short range but inflicted great damage and could set targets on fire. They were useful in close-quarters combat and attacks on caves and bunkers. They were also effective in boarding operations.
For all their power, flame projectors had a key weakness. Because they employed volatile chemicals under pressure, the weapon could sometimes explode if damaged.
Flamethrowers were extremely useful against lightsaber wielders as the flame could not be blocked by a blade. A skilled enough Force wielder could use the Force to shield themselves from the flames, but this took considerable effort and uncommon strength in the Force.
Many Mandalorians

Mandalorian Organization Mandalorians

and bounty hunters

Bounty Hunter Organization Communities

had similar flamethrowers installed on their armors.