The Slant/Fin VSL II is a stainless steel, modulating, condensing gas boiler stands at the top in performance, safety and environmental ratings. This Energy Star rated, high efficient boiler is equipped with a stainless steel fecralloy fiber mesh burner and is available for natural or propane gas. The ASME Stainless steel heat exchanger has unparralled resistance to corrosion. A proven European Design packaged and designed for an American Company to serve the American people is sure to satisfy your requirements.