- Heavy duty Million Air stainless-steel, tubular heat exchanger - Stainless steel secondary heat exchanger - Two-stage convertible gas valve automatically adjust to high or low stage - Durable SureStart 110 volt Silicon Nitride Igniter - Quiet single-speed induced draft blower - Multi-position installation: downflow,horizontal left or right - Heavy gauge steel cabinet with durable baked-enamel finish - Cabinet air leakage (QLeak) = 2% - Fully insulated heat exchanger and blower section