High output with lots of flexibility. 40,000 BTU/hr of heat is ducted to three separate areas of the boat keeping everyone warm and toasty. Kit features: 12V, DC, three-speed or optional 24V three-speed fan. Heater housing is constructed of heavy-duty marine grade aluminum and powder coated to prevent corrosion. Heat is ducted from three, 3" outlets through three adjustable Hot Tube™ vents.