the air and healthy performance of your Broan ventilation fan or range hood using one of our bird's-eye variety of canal accessories. 7 '' spherical epithelial duct comes in 2-foot extended sections for convenient installation Duct is of 28 gauge startled aluminous for durability and extended life sold as 5 sections per carton Operating System Batteries Included Batteries needed Number of Batteries Battery Type Language Assembly needed .