Majestic UD6, 6" (152mm) uninsulated flex duct for use with outside air kit - includes two 42" (1065mm) sectionsThe Majestic UD6 Uninsulated Flex Duct is a reliable solution designed to enhance the performance of your Majestic fireplace when paired with an outside air kit. This 6 inch (152mm) flex duct includes two durable 42 inch (1065mm) sections, providing flexibility and ease of installation for bringing fresh outside air into your fireplace system. By improving combustion airflow, the UD6 helps optimize fireplace efficiency and maintain a consistent burn.