Not all homes are constructed with the same parameters. The Windster H Series Extension Duct Cover is here to help even the playing field. Your new Windster H-series range hood comes with a duct cover for average ceilings; this handy extension kit is provided for taller ceilings between 9- and 10.5-feet high. The duct cover is made from durable, solid stainless steel and is welded together for a seamless design without sharp edges. The duct cover has been approved for use by the CSA for use in both US and Canadian homes.