Exhaust Roof Vent Kit is designed for a complete roof ducting installation of exhaust fans with 3" or 4" duct connectors. This kit includes a black steel roof cap featuring a built-in back draft damper and bird screen, a 4" diameter metal duct connector, and two nylon zip ties. It also comes with a 3" to 4" duct adapter and eight feet of 4" diameter flexible foil ducting that meets UL181 Class 1 air connector requirements. Additionally, a neoprene foam strip is included to increase the duct diameter when attaching to a fan with a 3" duct collar. Please note, this kit is not for dryer or range hood venting. Model Number: RVK1A