Combustion Air Intake System For Fuel Type Natural Gas and Oil Maximum Appliance BtuH Input 910 000 BtuH Maximum Airflow 900 cfm Nameplate Voltage 120V AC Compatible System 120V Appliance Inlet Diameter 8 in Outlet Diameter 8 in Oil Appliance BtuH Input Max of 900 MBH or 6.5 GPH Natural Gas Appliance BtuH Input Up to 910 000 BtuH Minimum Vent Pipe Diameter 8 in Maximum Vent Pipe Diameter 12 in Overall Height 19 1/2 in Overall Length 14 in Overall Width 15 1/2 in