The combustion process is completely isolated from the inside of the boat by the unique, direct vent design. A built-in blower provides good heat circulation. The heater is sold with all accessories needed including a stainless steel backing plate, 28" of flexible double stainless chimney and the deck fitting cap. A propane hose, 11" WC regulator and fittings are needed and sold separately.8-1/2" W x 14 H x 5-1/2" D Mounting Backplate Easy to install - Easy to useStainless Steel burnerLarge ceramic glass viewing window with safety screenSafe, direct-vent operationUnaffected by motion or windVariable heat output and excellent thermal efficiency.Low fuel consumptionCompact design, with attractive appearance, made of 304 stainless steel.No interior oxygen depletion