Non-Duct Kits Help To Recirculate Air In Situations Where A Hood Must Be Installed As Non-Ducted. Change Filters Regularly To Keep The Kitchen Fresher. (Ul)(Li)For Use With Wtt32I36Sb Or Wtt32I42Sb Chimney Hood(/Li)(Li)Kit Includes 8" Round Metal Flex Duct, Diverter And Filters For 36" Or 42" Hood(/Li)(Li)Use Non-Duct Replacement Filters, Afcwtt326 For The 36" Or 42" Hood (Pack Of 2)(/Li)(/Ul)