Duct and fittings direct airflow through the HVAC system and are made with rigid or flexible materials, depending on the application and installation requirements. Rigid ducts and fittings are durable and better suited for harsher conditions and transporting materials. Flexible ducts can route around obstacles, making them ideal for smaller utility spaces such as residential and light commercial applications. Fabric duct and fittings are flexible, breathable ducts that are quickly and easily installed. Similar to flexible ducts, they are best suited for light duty, temporary applications.