Tapered, round reducer for use between 8-inch to 7-inch or 10-inch to 8-inch or 7-inch to 6-inch round ducts. Duct reducers are used when you need to change from one size duct to another size, maintaining maximum airflow through your system while changing to the needed duct size to get into tighter spaces. Please check your Zephyr range hood's specification sheet to ensure compatibility.