Are Flamethrowers legal? YES!!! In fact, in 48 states they require no background check and can be shipped directly to your door! (Not legal in California or Maryland, sorry).
This is the very popular Pulsefire UBF flamethrower, which is battery operated and runs on regular ol' gasoline. Can be used hand-held or MOUNTED ON YOUR AR!!!!! 25-foot range with arc ignition, safe, dependable, fun and functional! Can be used to melt snow and ice, burn weeds, etc., lots of practical uses.