Airflow Systems Butterfly Valve Ducts are specifically designed to maximize airflow when cooling is needed and restrict it when it isn't. Working in tandem with our ductwork's smooth transition designs, the integrated butterfly valve gives you precise control over airflow while adding a clean, finished look to your oil cooling system. *This product is intended for anyone who's configuration will NOT accommodate our standard design; 45 degree hose outlet orientation. Please email your ductwork requirements and photos to Airflowsystems2@gmail.com for pricing inquiry