Model B355T features 5 lbs of aviation industry standard Halon 1211. Twice the firepower of the larger B394TS Halotron 1 model. Halon is a "Clean Agent" – a gaseous fire extinguishant that does not leave a residue. Halon is extraordinarily effective in putting out flammable liquid and electrical fires. As a liquefied gas, Halon is able to effectively fight hard to reach fires by chemically disrupting combustion.