RV Electric Heater Add-on Atwood 8500 Series "Ducted/Plenum System" Ducted/Plenum (AT-10) Cabinet Adapter for Atwood 8500 Series Gas Furnace Multi-Tap Electric Heater (3-Heat Selections, 2-Voltage Selections) CheapHeat Smart Controller, Change Over Switch Wire Harnesses, Misc. Mounting Hardware, Wire Clamps Installation and Safety Manual