What's Included Anti-Draft Shield Features Heating Efficiency Increased By 70% Virtually Eliminates Carbon Monoxide Exclusive Green HearthCAT Technology! Adjusts to fireplace back wall measuring 22"-31" Reduces Current Particulate Emissions By Approximately 75% PureFire Catalyzes All Organic Compounds (PM And CO) And Allows Cool Ambient Air To Bypass Catalyst Specifications Item Number AH2231P  Product Type Hood