The DBF has a reloadable canister filled with magically compressed hydrogen. The canisters must be very heat resistant or they will blow up. When the trigger is pulled the gas is released through a series of tubes which leads out the barrel and past a dragon tooth. The tooth still retains the special minerals that live dragons use to breath fire. The gas is ingited and fire burns the target. It's very light so its does'nt need a heavy strap or anything.
with it's light wieght and easy to use it can be used as either a main weapon or a sidearm. Either way the enemy is toast.
As many flamethrowers are heavy and require large packs to use it. The DBF has taken away that flaw and made flamethrowers far easier to use.